indot research program benefit cost analysis – … 17 roi final report 12...5 * based on indot 5...

INDOT Research Program Benefit Cost Analysis – Return on Investment

For Projects completed in FY 2017

(SPR – 4225)

This Annual Return on Investment (ROI) Report for the INDOT Research Program was prepared

at the request of the Governor’s Office and INDOT Executive Staff

Bob McCullouch PE, Ph.D.

School of Civil Engineering

Purdue University

December 2018

i

Table of Contents

Introduction ..................................................................................................................................................... 1

Benefit-Cost Analysis Methodology ................................................................................................................. 1

Benefit-Cost Analysis Results ........................................................................................................................... 2

Individual Project Analysis ............................................................................................................................... 2

Summary .......................................................................................................................................................... 6

Appendix .......................................................................................................................................................... 7

Individual Project Analysis .................................................................................................................. 9

SPR-3310: Investigation of Use of Slag Agregate and Slag Cements in Concrete Pavements

to Reduce Their Maintenance Costs ................................................................................................... 9

SPR-3811: Moisture Strength Constructability Guidelines for Subgrade Foundation Soils

Found in Indiana ……………………………………………….………………………………………………………………….…….13

SPR-3818: Cost Benefit Analysis and Implementation of NDT Testing of INDOT Bridge ……….……….15

SPR-3833: Site Selection for New Lighting Technologies………………………………………………………………..18

SPR-3866 : Performance of Alternative Diamond Interchange Forms ……………………………….…………21

List of Tables

Table 1. Quantitative Benefits Projects List ……………………………………………….……………….…………………………..3

Table 2. Agency Savings Projects ……………………………….…………………………………………………………………………….4

Table 3. Safety/RUC Savings Projects …………………………………..………………………………….………………………5

Table 4. Complete Research Project List – FY 2017…………………………………………………….………………………7

1

Introduction

The Governor’s Office requested an annual financial analysis of the INDOT Research Program to

determine the return on the research investment (ROI). The current financial analysis is for research

projects that completed in FY 2017. Analyses on previous year’s projects is necessary primarily due to

the time it takes some project outcomes to be implemented extending into the following year.

Therefore, the FY 2017 analysis is completed in calendar 2018. The ROI analysis will supplement the

annual IMPACT report (qualitative and quantitative benefits) by adding a more rigorous quantitative

benefit cost analysis (BCA) to the Research Program. Previous financial analyses used the approach of

calculating net present values of cash flows to determine a benefit cost ratio and this report uses the

same approach. Additionally, an overall program rate of return (ROI) is reported and will be

accumulated over time into a rolling 5-year average.

While the quantitative benefit cost analysis (BCA) was rigorous, results are limited to projects where

benefits and costs could be quantified. Qualitative benefits are highlighted in the companion annual

IMPACT report (https://www.in.gov/indot/2404.htm )

The agency savings generally would be expected to be used to select other construction projects (or

other activities) that would otherwise have to be deferred to later years. Frequently, research projects

that have the likelihood of saving large amounts of dollars in initial or long term maintenance costs,

which essentially allows us INDOT fund other projects more fully or sooner.

Benefit-Cost Analysis Methodology

All FY 2017 completed projects were reviewed to determine if they were a viable candidate for BCA.

Selection was based on 1) can the costs and benefits be quantified on outcomes that impact INDOT

operations, 2) what are the implementation costs, and 3) what is the expected impact time period?

The ROI analysis included the following savings components:

o Agency savings and costs. This was based on research findings, engineering

judgment/estimates from INDOT BO (business owner) and SME (subject matter

experts), available data, and projected use of the new product/process.

o Road User Costs (RUC) Savings. RUC includes value of time (VOT), and vehicle operating

costs (VOC). RUC unit values will be obtained from current INDOT standards which

INDOT provided.

o Safety Costs (SC) Savings. Safety costs (SC) can include a before and after evaluation or

engineering judgement from BO/SMEs to calculate the reduction in crashes (e.g.

property damage, fatalities, etc.). SC unit values will be obtained from current INDOT

standards which INDOT provided.

Accrued Benefits will be the combination of Agency savings, RUC cost savings, and SC savings. While

Road User Cost (RUC) savings and Safety Cost (SC) savings are a primary goal of INDOT, savings accrued

primarily benefit the customer (road user) and may not result in agency cost savings. In this year’s

analysis only 3866 reported RUC and SC savings. A separate B/C ratio is calculated for Agency Savings

and Safety/RUC Savings. Safety and RUC savings are often related, these savings were combined into

the same category.

2

Quantitative benefits were calculated for each research project analyzed for the expected impact period

where known or planned quantities (estimated in the INDOT Work Program) were available. A five-year

analysis period was used on one of the projects, a seven-year period on another, and a 14 and 20 year

period on two others. These analysis periods are explained in their individual analysis. Individual project

costs are research and implementation costs. Net present value (NPV) for individual projects are

calculated to 2017 dollars by combining costs and benefit cash flows. Individual project analyses are

included in the Appendix. Backup documentation describing calculations and analysis for qualifying

projects will be kept by the INDOT Research and Development Division and are available for review.

The ROI is expressed as a BCA ratio, which is commonly used by State DOTs and national transportation

research agencies when expressing the return on the research investment. This methodology will be

used annually to calculate a FY ROI which will be combined with other FY ROI to create a rolling average

over time. The rolling average will accumulate up to a maximum of the five recent years, with FY 2016

being the first year.

Benefit-Cost Analysis Results

Project outcomes were classified as either Quantitative, Qualitative, or Not Successfully Implemented.

• Quantitative - Implementation produces benefits that are measureable and quantifiable. Each

of these projects has an individual analysis performed and is included in the Appendix. The

analysis or impact period is the time benefits were calculated.

• Qualitative - Implementation is successful and benefits occur, but cannot be quantified with

certainty due to data not being available or easily discoverable. Examples of qualitative benefits

could include a specification revision, a new test method, a proof-of-concept study, a synthesis

study that produces a summary of options and best practices, manuals or guidelines, or where

cost comparison data is unavailable.

• Not Successfully Implemented - For various reasons the project outcomes could not be

currently implemented. Common reasons are management, logistical, technical, or legal issues.

Individual Project Analysis

Table 1 is the list of the six projects where benefits (NPV 2017$ - NPV of future cash flows in 2017

dollars) could be quantified and their individual analysis is found in the Appendix. Table 4, in the

Appendix, is a complete list of all 24 projects completed in FY 2017.

Two of the projects have a five-year analysis period. On these projects the annual benefits were based

on planned installed quantities that resulted in immediate savings, such as construction cost savings.

Project 3310 analysis period is based on the expected time to longitudinal joint rehabilitation in

concrete pavements, which based on current project data, is currently occurring every 20 years. Project

3833 has a 14 - year analysis period which is the expected life of LED lighting fixtures. Project 3866 has a

seven-year analysis period because INDOT Traffic Engineering has estimated the number of diamond

interchanges to be built during this time period.

3

Table 1. Quantitative Benefits Project List

No

FY 16 Completed & Implemented

SPR Projects

Project Cost TITLE Benefit Type

Analysis

Period

NPV Project Benefit ($1000)

2017$

($1000)

1 3310 $202

Investigation of Use of Slag Aggregate and

Slag Cements in Concrete Pavement to

Reduce Their Maintenance Costs

Agency Savings 20 Years $51,310

2 3811 $250

Moisture Strength Constructability Guidelines for

Subgrade Foundation Soils Found in Indiana

Agency Savings 5 Years $242

3 3818 $153

Cost Benefit Analysis and Implementation of NDT Testing of INDOT

Bridge Decks


4 3833 $136 Site Selection for New Lighting Technologies


5 3866 $160 Performance of

Alternative Diamond Interchange Forms

Agency Savings

RUC Savings 7 Years

$27,747 (Agency)

$11,247 (RUC)

Total Benefits $200,935,000

Agency Benefits $189,688,000

Road User Benefits $ 11,247,000

Agency Savings

The total quantifiable savings from the five projects resulting in agency savings, during their analysis or

impact period, was calculated at $189,688,000 (in 2017$). The total research program cost in FY 2017

was $3,944,000. Therefore, the agency savings BCA for FY 2017 is: $189,688,000 /$4,124,000 = 46, or

46 dollars in agency savings for every research dollar expended.

Safety/RUC Savings

The total quantifiable savings from the one project (3866) resulting in safety/RUC savings, during the

analysis or impact period was calculated at $11,247,000 (in 2017$). The total research program cost in

FY 2017 was $4,124,000. Therefore, the safety/RUC savings BCA for FY 2017 is:

$11,247,000/$4,124,000 = 3, or 3 dollars in safety/RUC savings to our customers for every research

dollar expended.

4

A table for each savings category was created, five projects cash flows classified as Agency Savings

(Table 2) and one project (3866) produced Agency and RUC Savings (Table 3). A condensed version of

the tables are shown. The expanded version of each table is included in the Appendix with the project

write-ups.

Table 2. Agency Savings Projects

Project Description FY2017 FY2018 FY2019 FY2020 FY2021

3310 – Annual Benefit (20 Year

impact)* 1. 312,500 321,875 331,531 341,477 351,722

Research and Implementation

cost -202,000

0 0 0 0

Net Benefit 110,500 321,875 331,531 341,477 351,722

NPV FY 2017 51,310,085

3811- Annual Benefit (5 year

impact)* 100,000

103,000 106,090 109,273 112,551


cost -250,000

Net Benefit -150,000 103,000 106,090 109,273 112,551

NPV FY 2017 242,718

3818 - Annual Benefit (5 year

impact)* 51,000,000 59,000,000 94,000,000 127,000,000 26,000,000


cost 1,077,000

-951,720 -980,272 -1,009,680 -1,039,970

Net Benefit 49,923,000 58,048,280 93,019,728 125,990,320 24,960,030

NPV FY 2017 99,999,000

3833 – Annual Benefit from

INDOT Construction Contract T-

40681-A 2.

0 0 837,468 1,108,832 888,470


Cost -315,000

Net Benefit -315,000 0 837,468 1,108,832 888,470

NPV FY 2017 10,930,916

3866- Annual Benefit (7 Year

impact) ** 3. 300,000 8,300,000 6,400,000

7,

700,000 2,100,000


Cost -153,000

Net Benefit 147,000 8,300,000 6,400,000 7,700,000 2,100,000

NPV 2017 27,747,000

NPV Total 2017

$189,688,000

Research Program Cost $4,124,000

Benefit Cost Ratio - ROI 46

Report Date 12/31/2018

5

* Based on INDOT 5 Year Work

Program

** Based on 7 Year projection

1. The first 5 years of the 20-year cash flows are shown. See supplementary file for the

additional cash flows.

2. The first 5 years of the 14-year cash flows are shown. See supplementary file for the


3. The first 5 years of the 7-year cash flows are shown. See supplementary file for additional

cash flows.

Table 3. Safety/RUC Savings Project - 3866

Project Benefits and Costs $ FY 2017 FY 2018 FY 2019 FY 2020 FY 2021 FY 2022

FY

2023

Research Cost -153,000

Annual User Cost Benefit 2,100,000 2,500,000 1,600,000 3,300,000 700,000 0 1,200,000

Net Benefit-Cost 1,947,000 2,500,000 1,600,000 3,300,000 700,000 0 1,200,000

NPV 2017 $11,247,000

Research Program Costs $4,124,000


As previously noted, five projects produce quantifiable benefits that result in agency savings. One

project also produces road user cost (RUC) savings. A summary of these cost savings are described

below.

• 3310 – New concrete mix design that includes slag cement and fly ash as a partial replacement

for Portland cement improves the durability of concrete pavements in the presence of deicers

and freeze thaw cycles. This increased durability will eliminate one joint repair project during

the life of a concrete pavement.

• 3811 - Change orders caused by excessive soil moisture during construction projects increase

construction costs for INDOT and cause unexpected delays. To alleviate these problems and

minimize change order costs associated with having unexpectedly high soil moisture conditions

at the time of construction, a methodology was developed to allow INDOT engineers to estimate

in situ soil moisture conditions early in the design phases of projects.

• 3818– Nondestructive testing (NDT) methods have been used by other state departments of

transportations resulting in more accurate condition assessments to base bridge deck repair and

replacement decisions on. This project evaluated the NDT approach and performed a cost-

benefit analysis of various NDT methods; and estimated the cost for establishing and operating

an internal NDT work group, and comparing it to using an external NDT consulting service.

• 3833 – This project determined the impact of changing INDOT roadway lighting fixtures from

high-pressure sodium (HPS) lamps to light emitting diodes lamps.

• 3866 – This study developed guidelines for screening and evaluating options for alternative

diamond interchanges. The guidelines provide a fair comparison procedure during the

preliminary planning and conceptual design stages and are used to determine the best

6

interchange form based on initial construction cost, traffic operations improvement, and user

travel time savings.

Summary

The aggregate benefit is significant, resulting in more than $200 million in savings over the projected

service lives (in 2017$). The aggregate benefit combines expected agency savings and expected savings

for users of the INDOT network. Direct agency savings of over $189 million is a return of $46 for every

$1 spent in research. For users, the return is 3 to 1 through lower user costs. The basis for the numbers

used in the BCA came from INDOT personnel, Industry Associations, and researchers. These are

described in detail in the individual analyses in the Appendix.

A ROI of 46 to 1 is considered a significant agency return on research investment, which is indicative of

other State DOT Research Programs. While the ROI is significant, a review of the individual project

analysis shows a conservative approach was taken in any assumption made and in the calculations, and

actual savings may be higher. This analysis indicates that INDOT is receiving a significant return on its

research investment which will continue to grow due to recently passed legislation (HB 1002),

authorizing more funding for construction, re-construction, and preservation, as more projects will be

impacted.

For the 19 projects completed in FY 2017, quantifiable benefits could not be calculated, however other

qualitative benefits resulted that brought significant value to the Department and are highlighted in the

annual IMPACT report. Five of the projects were quantified and described herein. A complete listing of

all research projects completed in FY 2017 is shown in Table 4 in the Appendix.

Rolling Average BCA

Annual BCA provide an assessment of INDOT’s investment in Research on an annual basis. For the last

two years, 2016 and 2017, the investment indicates positive returns during the life of individual projects

implemented. The majority of the projects in the last two years, 48 out of 66 total research projects

benefits are not quantifiable due to the unavailability of quantifiable data, but provide documented

qualitative benefits. 13 projects where benefits were quantified, produced significant agency savings

and 3 projects produced significant road user cost savings. For the combined years of 2016 and 2017

the Agency and Road User BCA are:

BCA (2016 and 2017) Agency Savings = $266,149,000/$10,388,000 = 25 to 1

BCA (2016 and 2017) User Savings = $301,990,799/$10,388,000 = 29 to 1

BCA Rolling Average – 2016-2017

Year Research Investment Agency Savings User Savings

2016 $6,264,000 $76,481,000 $290,743,799

2017 $4,124,000 $189,668,000 $11,247,000

Totals $10,388,000 $266,149,000 $301,990,799

7

Appendix

Table 4. – Complete Research Project List – FY 2017

No

FY 17 Completed & Implemented SPR Projects

Project Title Project

Cost ($ 1000)

Quantitative Benefits,

Qualitative Benefits or Not Successfully Implemented

Project Benefits ($1000)

1 3310

Investigation of Use of Slag Aggregate and Slag Cements in Concrete Pavement to Reduce Their Maintenance Costs

$202

Quantitative

51,310

2 3319 Assessment of the Performance of MSE Abutment Walls in Indiana

$185 Qualitative Benefits

0

3 3320

Development of a Cost Effective Bridge Preservation and Rehabilitation Program

$341 Qualitative

Benefits

0

4 3702 Strategies for Grouping of Transportation Projects

$170 Qualitative

Benefits 0

5 3714 Guardrails for Use on Historic Bridges


0

6 3728 Sulfates in Indiana Substrates


0

7 3801

Using Field Electrical Conductivity Measurements for Scheduling Chip Seal Spreading/Sweeping Operation

$150 Qualitative

Benefits 0

8 3811

Moisture-Strength-Constructability Guidelines for Subgrade Foundation Soils Found in Indiana

$250 Quantitative 242

9 3814 Ecologically-aware Design of Waterway-encapsulating Structures

$116 Qualitative

Benefits 0

10 3818

Cost Benefit Analysis and Implementation of NDT Testing of INDOT Bridge Decks

$153 Quantitative 99,999

8

11 3823 INDOT‐‐‐‐JTRP LPA Process Improvement


0

12 3831 Safety Data Acquisition and Management (Data Portal and Tscan)

$400

Qualitative Benefits

0

13 3833 Site Selection for New Lighting Technologies

$315 Quantitative 10,930

14 3853 CAI/S-BRITE Pad/Site Development Project

$460 Qualitative

Benefits 0

15 3858

A Mobile Concrete Laboratory to Support Testing in 2014 on Internal Curing and High Early Strength Patches

$110 Qualitative

Benefits

0

16 3866 Performance of Alternative Diamond Interchange Forms

$160 Quantitative

$27,747 (Agency) $11,247 (RUC)

17 3900 Variable Speed Limit Feasibility Study


0

18 3940

Chemical Modification of Uniform Soils and Soils with High/Low Plasticity Index

$130 Qualitative

Benefits 0

19 3946 Improving Energy Efficiency of Facilities

$50 Qualitative

Benefits 0

20 3947 Precast Slab Pilot Implementation

$10 Qualitative

Benefits 0

21 3948 Pre-Contract Scoping Processes Value Stream Mapping

$49 Qualitative

Benefits 0

22 4000 Mechanic/Maintenance Training and Certification Program

$77 Qualitative

Benefits 0

9

23 4152 Pavement Density Demonstration Project

$7 Qualitative

Benefits 0

24 4159

Evaluation of alternative LiDAR platforms and sensors for Asset Management

$9 Qualitative

Benefits 0

$4,124

Total 2017 Research spending is $4,124,000.


SPR-3310: Investigation of Use of Slag Aggregates and Slag Cements in Concrete Pavements to Reduce

Maintenance Cost

Introduction

This study evaluated the use of ground granulated blast furnace slag (GGBFS) called slag cement as a

replacement for cement and its long-term effect on concrete pavements. Based on laboratory tests

using GGBFS/slag cement and fly ash together as a partial replacement for Portland cement, these

materials improved concrete strength while increasing concrete durability in the presence of deicers and

freeze thaw cycles. Damage typically occurs at the pavement longitudinal joint making joint repairs

more frequent which will be minimized through this approach.

By using a combination of GGBFS/slag cement and fly ash, savings in concrete materials and increased

pavement durability occurs. The increased durability indicates that for a typical concrete pavement life

(50 years) one joint repair can be avoided. The benefit cost analysis is based on initial material savings

and increased joint durability.

One outcome of this project was the development of a unique special provision for Section 501 adopted

in January 2017 that allows for the use of GGBFS.

Analysis

Based on past concrete pavement quantities and current estimates an average of 1.5 million SYD of

concrete pavement is estimated to be placed annually in the five-year INDOT work plan. Estimated

savings comes from initial material savings and long-term maintenance savings.

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Calculations

Annual Material savings – average pavement thickness is 12”

1,500,000 SY1 (Estimated concrete pavement) x (12”/36”) = 500,000 CY

500# cement/CY x 500,000 CY = 125,000 tons of cement required

@25% fly ash replacement for cement = 125,000 x .25 = 31,250 tons fly ash

@75% cement = 125,000 x .75 = 93,750 tons of cement

Estimated that slag cement will replace fly ash at a 50% rate – 31,250/2 = 15,625 tons1

Cement cost is approximately $125 a ton1

Slag cement cost is $100-$110/ton1

Fly ash cost is $65-$80 a ton1

Calculate savings by using slag cement over regular cement, initial cost savings –

Slag cement average cost is an average of $105/ton

Cost savings = $125 - $105 = $20/ton

Annual estimated material cost savings = $20/ton x 15,625 tons = $312,500

Longitudinal Joint Repair Savings- During pavement life

Based on current joint repair contracts this avoidance will occur at year 20 in the pavement life, so cost

savings will be calculated at that point in time and brought back to a 2017$ net present value.

Contract R 41350 (I-465 on the southwest side of Indianapolis) was bid in August 2018. Concrete joint

repair was a work item and there were three bidders. The lowest bid for joint repair was $382 per

square foot and using a one-foot wide trench, the linear cost translates to $38 per linear foot. This cost

can be eliminated in year 20 of the pavement. To determine this savings the 20-year unit cost is

increased due to inflation at a 3% annual rate. The estimated 20 year unit cost = $38 (F/P, 3%) =

$38*1.8061 = $68 LF.

For 1,500,000 SYD of pavement and assuming a 24 ft. wide pavement, the linear foot of longitudinal

joint is:

1,500,000 SYD x 9 SF/SYD = 13,500,000 SF / 24 FT (pavement width) = 562,500 LFT of longitudinal joint.

Concrete joint repair contracts indicate that not 100 % of the joint needs to be repaired, it varies

between 50% – 75% of the total joint. Using the lower percentage produces a conservative repair cost

saving.

The longitudinal joint repair cost, at year 20 is 562,500 LFT * (50% replacement rate) X $68/LFT =

$19,125,000.

11

3310 - 20 year life

FY2017 FY2018 FY2019 FY2020 FY2021 FY2022 FY2023 FY 2024 FY 2025 FY 2026 FY 2027 FY 2027 FY 2028

Research and Implementation cost -202,000

Material Savings 312,500 321,875 331,531 341,477 351,722

Maintenance Benefit - 2017 pavement 0 0 0 0 0 0 0 0 0 0 0 0

Maintenance Benefit - 2018 pavement 0 0 0 0 0 0 0 0 0 0 0 0

Maintenance Benefit - 2019 pavement 0 0 0 0 0 0 0 0 0 0 0

Maintenance Benefit - 2020 pavement 0 0 0 0 0 0 0 0 0 0

Maintenance Benefit - 2021 pavement 0 0 0 0 0 0 0 0

Net Benefit-Cost 110,500 321,875 331,531 341,477 351,722 0 0 0 0 0 0 0 0

FY 2029 FY 2030 FY 2031 FY 2032 FY 2033 FY 2034 FY 2035 FY 2036 FY 2037 FY2038 FY2039 FY2040

0 0 0 0 0 0 0 19,125,000

0 0 0 0 0 0 0 0 19,125,000

0 0 0 0 0 0 0 0 0 19,125,000

0 0 0 0 0 0 0 0 0 0 19,125,000

0 0 0 0 0 0 0 0 0 0 0 19,125,000

0 0 0 0 0 0 0 19,125,000 19,125,000 19,125,000 19,125,000 19,125,000

NPV 2017 $51,310,085

Benefit Cost Ratio 254

12

Summary

The benefit cost ratio for this project is 254 to 1. The number is based on the following:

• Research cost of $202,000.

• 5 Year work program scheduling pavement estimates were used at 1.5 million SYD per year.

• Concrete joint repair cost is based on 2018 unit bid cost.

• 3% cost of capital

• 3% annual inflation rate

• NPV of future costs and benefits brought to 2017$.

This analysis is only for this project’s cost to execute research and implement. In the summary report an

overall 2018 benefit cost analysis is based on total program costs.

References

1 Provided by Mike Byers, Executive Director of Indiana Chapter of the American Concrete Pavement

Association.

2 INDOT bid tab, August 8, 2018, Contract ID: R-41350-A.

SPR-3811: Moisture-Strength-Constructability Guidelines for Subgrade Foundation Soils Found in

Indiana

Introduction

Construction activities become difficult when the soil moisture content is excessive, especially in fine-

grained soils. Change orders caused by excessive soil moisture during construction projects increase

construction costs for INDOT and cause unexpected delays. To alleviate these problems and minimize

change order costs associated with having unexpectedly high soil moisture conditions at the time of

construction, a methodology was developed to allow INDOT engineers to estimate in situ soil moisture

conditions early in the design phases of projects.

The soil moisture prediction methodology is based on results from soil moisture flow simulations carried

out using the HYDRUS-1D software. The results obtained from initial soil moisture flow simulations were

validated using field measurements from six test sites located in Indiana where soil property data was

available and continuous in situ soil moisture measurements at multiple depths were available for up to

3 years (2011-2014). Agreement was found between moisture content measurements and predictions.

After validation of the developed moisture prediction methodology, ten-year moisture content

simulations using HYDRUS 1D were performed for typical profiles in each county in Indiana using input

weather data from the climate database, groundwater data from Department of Natural Resources

(DNR) database and soil properties from Indiana Geological Survey (IGS), INDOT and the Soil Survey

Geographic (SSURGO) databases. Yearly results from these ten-year soil moisture flow simulations were

then overlapped to ascertain how the profiles of the in situ soil moisture content within the depth of

interest varied monthly within this period of time, in each county. Using these results, constructability

criteria was developed that is based on determining how the in situ soil moisture content deviates from

13

the optimum soil moisture content obtained from standard Proctor compaction tests. This criteria is to

be used to determine expected soil moisture levels at the design phase that can eliminate costly

geotechnical change orders.

Analysis

To determine the frequency and magnitude of wet subgrades or high soil moisture conditions and their impact on INDOT construction projects and associated costs; a list of geotechnical change orders was obtained from INDOT Geotechnical Services.1 Returned was a list of all geotechnical change orders for the years 2014-2017. From these change orders; those that were connected to high moisture content were analyzed to determine relevance and are summarized in the following table.

Date Change Order # Cost Problem

September 2017 B-31498 $42,062 Failed proof rolling due to wet subgrade

June 2017 R -37250 $7,335 Subsurface remediation required due to wet subgrade.

September 2016 R-33582 $140,183 Weak subgrade soils preventing pavement stability

2016 R-35411 $31,227 Subgrade pumping and not compactable.

2016 R-35968 $19,527 Subgrade too soft for compaction due to unforeseen wet conditions.

2015 R-34078 $22,898 Encountered quick sand and unstable soils due to high water table.

2015 RS-34356 $1,616 Soft and wet shoulder material.

2014 B-29487 $36,150 Unstable subbase due to moisture conditions.

2014 R-33562 $90,936 Wet sandy soils encountered requiring additional subgrade treatment and geogrid.

Total Change Orders = $391,934

During 2014-2017, a four-year time period there were nine change orders costing $391,934 caused by high moisture conditions. This is an average of approximately two per year at an average cost of $391,934/4yrs. = $97,983. For B/C calculation purposes $97,983 a year will be

14

the estimated cost savings by using the subgrade moisture guidelines developed in this project which are extended over a five-year work plan period.1 Calculations

Project Benefits and Costs FY 2017 FY 2018 FY 2019 FY 2020 FY 2021


Estimated Annual Change Order Savings 97,983 100,922 103,950 107,069 110,281

Net Benefit-Cost -152,017 100,922 103,950 107,069 110,281

NPV 232,927

Benefits Cost Ratio 1

Summary



• 5 Year work program.


• 3% annual inflation rate

• NPV of future costs and benefits (change order avoidance) brought to 2017$.



References

1Nayyar Zia Siddiki MS PE, Geotechnical Services Section

Ganju, E., Rahman, S., Prezzi, M., Salgado, R., & Siddiki, N. (2016). Moisture-strength-constructability

guidelines for subgrade foundation soils found in Indiana (Joint Transportation Research Program

Publication No. FHWA/IN/JTRP-2016/27). West Lafayette, IN: Purdue University.

http://dx.doi.org/10.5703/1288284316354

SPR-3818: Cost Benefit Analysis and Implementation of NDT Testing of INDOT Bridge Decks

Introduction

INDOT is required to inspect bridges every two years and has typically used visual based inspection

methods to evaluate the health of bridge decks. This method does not always accurately portray deck

health or possible damage that can lead INDOT to schedule deck repairs based on age in-lieu of more

definitive condition ratings. Nondestructive testing (NDT) methods have been used by other state

departments of transportations resulting in more accurate condition assessments to base repair and

replacement decisions on. This project evaluated the NDT approach and performed cost-benefit analysis

of various NDT methods with the current INDOT program; and estimated the cost for establishing and

operating an internal NDT work group, and comparing it to using an external NDT consulting service.

15

NDT technologies evaluated were: Infrared thermography (IR), Chloride ion penetration (CIP), Half-cell

potential, ground coupled GPR, Air-launched horn GPR, and impact echo with the IR, CIP, and GPR the

least expensive and used in the cost analysis.

Analysis

ROI analysis is based on comparing the current INDOT program scheduling of inspecting and repairing

bridge decks to using NDT inspection and repair based on condition results. INDOT deck repair program

is a schedule of repairs at designated age levels. For example one schedule is: overlay at 20 years; deck

replacement at 40 years; overlay at 60 years; and replace bridge at 80 years.

The INDOT program schedule (can result in) taking bridges out of service at the same time , earlier , or

later than using an NDT based program. A better average condition may exist through the current

INDOT program, however at a potentially higher cost because more actions could be performed that

could be reduced if repair decisions are based on NDT outcomes.

A network (total INDOT bridge inventory) cost based simulation using engineering economic principles

of net present cost (NPC) and equivalent uniform annual cost (EUAC) was performed for four different

bridge deck repair schedules. The lowest cost schedule is the one described above and shown in the

below table on an annual cost basis.

Calculations

EUAC ($)

Current INDOT Bridge Deck

Inspection and Repair

Program

203 Million

NDT Inspection and

Condition Based Repair

136 Million

NDT inspections provide more accurate and reliable condition reports, and better life-cycle costs which

can prevent unnecessary repairs and lower deck repair costs during the bridge life. The simulated cost

analysis shows an expected annual savings of 33% (1-(136/203)).2

Potential Savings

• Improved deck quality assessment

• Lower bridge lifecycle deck costs

Since INDOT does not have, an NDT inspection program, an initial and annual investment cost will occur.

Initial costs include NDT equipment, a van, inspection, data analyst personnel, and their training.

Annual costs is comprised of personnel, equipment maintenance, travel, and maintenance of traffic

costs. The equivalent uniform annual cost for the initial investment and annual maintenance cost for an

NDT program was calculated to be $924,000.2

16

The current five year work plan for bridge deck repair is shown in the below table. Estimated savings are

based on the simulated EUAC cost analysis performed by using an NDT inspection program.

2017 2018 2019 2020 2021

Estimated cost1 $155 M $179 M $287M $387M $81M

Estimated

Savings (33%)

$51M $59M $94M $127M $26M

Below is the benefit cost analysis for a five-year work plan.1 The analysis is based on a known five-year

work plan (2017-2022) and an NDT inspection program was used to determine deck repairs and not

based on age-based repairs, which is the current INDOT policy.

Project Benefits and Costs($) FY 2017 FY 2018 FY 2019 FY 2020 FY 2021


Annual NDT cost -924,000 -951,720 -980,272 -1,009,680 -1,039,970

Annual Benefit 51,000,000 59,000,000 94,000,000 127,000,000 26,000,000

Net Benefit-Cost 49,923,000 58,048,280 93,019,728 125,990,320 24,960,030

NPV 99,999,000


Summary

INDOT can realize significant cost savings by implementing an NDT based bridge deck inspection

program. The calculated savings are significant, but it indicates that INDOT should adopt an NDT

inspection program as soon as possible after making an investment to either establish an internal

program or outsource to a private company. The study calculated a break-even point of $0.22 per

square foot for a consultant to be competitive with an internal INDOT based program.

The benefit cost ratio for this project is 654 to 1. This number is based on the following:


• 3% cost of capital and inflation.




References

1 Estimated annual bridge deck costs provided by Adam Post, INDOT Bridge Asset Manager.

2 Taylor, B. R., Qiao, Y., Bowman, M. D., & Labi, S. (2016). The economic impact of implementing

nondestructive testing of reinforced concrete bridge decks in Indiana (Joint Transportation Research

Program Publication No. FHWA/IN/JTRP- 2016/20). West Lafayette, IN: Purdue University.

https://doi.org /10.5703/1288284316343

Professor Mark Bowman (PI) phone conversation, September 25, 2018.

17

SPR-3613: Cost and Energy Efficient Roadway Lighting

SPR-3833: Safety and Cost Performance of Intersection Lighting

SPR-4153: INDOT Highway Lighting Support Services

Introduction

SPR-3613 examined the viability of new, solid state lighting technologies for the state highway system,

determining whether adequate light levels could be obtained and confirming manufacturers’ claims on

the energy efficiency of their models. Findings of this project included: 1) at least some if not all of the

solid state models examined did provide adequate light levels- average maintained illumination, ratio of

average to minimum and 2) solid state models do use significantly less energy- in some cases less than

half of their High Pressure Sodium counterpart.

SPR-3833 investigated and analyzed the effect of lighting on intersection accidents and crashes. Crash

data from a ten-year period (2004 – 2013) shows that Indiana has a higher number of crashes in the

unlit intersections than neighboring states (73% to 38%) and the nation (73% to 34%). Field light tests

were performed at fourteen intersections producing maintenance recommendations and cost data.

One outcome was the development of crash modification factors to be used to perform a justification

analysis to determine the need for an intersection lighting project. To assist in determining this need an

excel worksheet was created that performs a life cycle cost analysis for an intersection lighting project.

The study also assessed the in-service performance of new lighting technologies and developed an

economic methodology to compare these technologies from a life cycle cost perspective. The benefit

cost analysis is based on this economic methodology and a current INDOT lighting retrofit contract.

Through extensive field demonstrations started under SPR-3613 and continued through SPR-3833,

INDOT found that most of the solid state models worked reliably- this was another concern of the

agency when first approached about the new technology.

SPR-4153 is an active project which provides for bench testing of solid state luminaires at the Purdue

Office of Energy Efficiency and Reliability, Northwest campus. This testing is of models that have been

formally submitted for INDOT Approved Materials List. Successful completion of the bench test is a

prerequisite for a model to be placed on the list and in turn a model must be on the list for it to be used

on a contract. To date 26 models have been or are currently being tested.

Analysis

INDOT Construction Contract T-40681-A, let May 10, 2018, repaired and replaced lighting fixtures in the

Greenfield District.1 Contract amount was $5.3 million with work to be completed by June, 2019. Of the

$5.3 million contract total $5.1 million was spent on the luminaires and work associated with converting

to solid state.

The number light fixtures included in this contract relative to function are:

2,315 of High Lumen Roadway

1,822 of High Mast Lighting

1,324 Low Lumen Roadway

695 Underpass Lighting

18

A total of 6,156 highway light fixtures are being replaced. This is approximately 40% the number of

INDOT light fixtures state-wide.

The final report for SPR-38332 included a life cycle cost analysis (LCCA) of a lighting retrofit project which

is what the above contract is. The LCCA compared existing light fixtures that INDOT uses, high-pressure

sodium (HPS) lamps with new technology options, light emitting diodes (LED). HPS lamps consume

more energy and have a shorter life span when compared to LED lamps. Basic assumptions used in the

calculations were:3

• Existing HPS fixtures have their lamps replaced every three years and LED options lamps last

longer, replaced every five years.

• Annual operating time for lamps is 4380 hours

• Indiana electricity price is $0.10/kWh.

Final report Table 7.82 shows the result of the EUAC analysis results, this is for the life of the fixture, 25

years.3

Lamp Type EUAC EUAC Savings

HPS 250W – High wattage $354.25 -----

LED 168W – High wattage $343.10 $11.15

LED 80W – Low wattage $277.99 $76.26

Calculations

To estimate the impact of the research implementation through statewide upgrade to LED some

adjustments need to be made to the assumptions used on the EUAC calculations in SPR-3833:

• Service life of the new solid state luminaire should be estimated at 14 years this equates to the

design year for the light level calculations. Presumably after 14 years INDOT will have to

modernize again as light output will have diminished below acceptable levels by that time.

• While existing HPS fixtures are re-lamped every three years LEDs are not replaced but the

lenses/refractors have to be cleaned approximately every 5 years- cleaning can be estimated at

$50 per cleaning per luminaire.3

The following energy consumptions are from the LED luminaire models selected by the winning bidder

for T-40681:

High Mast: reducing from 1104 W from HPS to 646 W for LED

High Lumen: reduce from 468 W (HPS) to 251 W (LED)

Low Lumen: reduce from 305 W (HPS) to 194 W (LED)

Underpass: reduce from 183 W (HPS) to 125 W (LED)

19

Potential Savings

• Reduced crashes resulting in Safety benefits for users,

• Decision tool for technology choice on intersection lighting.

• Annual savings from reduced electrical consumption and longer life light sources.

Below is the benefit cost analysis for implementing research results into one lighting contract. The

calculations are based on electricity savings and the cost of cleaning the LED fixtures every 5 years.3

Annual electricity Cost

Savings

Based on $0.10/kWh and 4380 hours of use

annually

HPS

Wattage

LED

Wattage Difference

#

Fixtures

Annual Electricity Cost

savings

High Mast 1104 646 458 1822 $365,500

High Lumen 468 251 217 2315 $220,031

Low Lumen 305 194 111 1324 $64,370

Underpass 183 125 58 695 $17,656

Total

fixtures 6156 $667,558

Total savings

all fixtures

LED fixtures require cleaning every five years with estimated cost3 at $75 (future) each, making the total

cost = $75 * 6156 (# of fixtures) = $461,700. The next page shows the cash flow analysis for a 14-year

period which is assumed the life of the lighting system (fixture).

Annual maintenance costs3 are different for the HPS and LED lights. Annual maintenance costs for HPS

fixtures is $60 each. Annual maintenance cost for LED fixtures are $50 for high mast and $25 for the

remaining fixtures. Maintenance cost savings calculation is shown in the below table.

High Mast Roadway

# fixtures 1822 4334

HPS Maintenance cost /fixture $60 $60

LED Maintenance cost/fixture $50 $25

Maintenance cost savings $10 $35

annual savings $18,220 $151,690

Total annual savings $169,910

Another cost savings is bulb replacement. HPS bulbs are replaced every three years at a cost of $40 3

each while LED bulbs are not replaced. Bulb and maintenance cost savings are included in the 14-year

analysis period.

20

14 year LED fixture life

FY 2017 FY

2018

FY

2019

FY

2020

FY

2021

FY

2022

FY

2023

FY

2024

FY

2025

FY

2026

FY

2027

FY

2027

FY

2028

FY

2029

FY

2030

FY

2031

Research and Implementation cost -315,000

5 Year cleaning cost -461,700 -461,700

HPS Bulb replacement cost savings 246,240

246,240 246,240 246,240 246,240

Maintenance Cost Savings 169,910 175,007 180,258 185,665 191,235 196,972 202,881 208,968 215,237 221,694 228,345 235,195 242,251 249,519

Electricity Cost savings 0 667,558 687,585 708,212 729,459 751,342 773,883 797,099 821,012 845,643 871,012 897,142 924,056 951,778 980,331

Net Benefit-Cost -315,000 0 837,468 1,108,832 888,470 915,124 727,118 970,855 999,981 1,276,220 1,060,879 631,006 1,371,727 1,159,252 951,778

1,476,090

NPV 2017 $10,930,916

Benefit Cost Ratio 35

This benefit cost calculation is based on the one contract previously described. This contract represents approximately 40% the state-wide

existing fixture inventory, so the calculated benefits can be multiplied by 2.5 to determine potential statewide impact of research

implementation.

Summary

The benefit cost ratio for this set of projects is 35 to 1. This number is based on the following:

• Total research cost of $315,000 ($54,000 for SPR-3613, $125,000 for SPR 3833, $135,000 for SPR 4153)


• NPV of future costs and benefits for a 14-year life of light fixtures brought to 2017$.

21

Improved roadway lighting has improved safety benefits for users which is not included in the benefit

analysis. The calculated benefit is an expected agency benefit.

The JTRP research directly influenced and enabled that technology retrofit of INDOT lighting in

Greenfield District, essentially from HPS to LED, for the purpose of reducing power cost and improving

lighting quality.

Additionally, the research included bench testing all candidate lamp models, allowing INDOT to build an

"approved products list" for future work. The research produced information to rewrite INDOT’s Design

Manual relative to use of emerging highway lighting technologies.

All future lighting contracts will benefit directly from this research.



References

1 Brad Steckler, INDOT Director of Traffic Engineering

2 Zhao, G., Li, S., & Jiang, Y. (2016). Safety and cost performance of intersection lighting (Joint

Transportation Research Program Publication No. FHWA/IN/JTRP-2016/17). West Lafayette, IN: Purdue

University. http://dx.doi.org /10.5703/1288284316340.

3 Lalit Garg, PE, Senior Engineer of Signing and Lighting and Dave Boruff, PE, Manager of Traffic

Administration Office.

SPR-3866 – Performance of Alternative Diamond Interchange Forms

Introduction

This study developed guidelines for screening and evaluating options for alternative diamond

interchanges. The guidelines provide a fair comparison procedure during the preliminary planning and

conceptual design stages and are used to determine the best interchange form based on initial

construction cost, traffic operations improvement, and user travel time savings.

Analysis

Thirty-six diamond interchanges are planned within a 7-year program/analysis period (2017-2023) that

could be plausibly considered as having benefited from the research project.1 The frequency of 36 over

7 years compares with historical counts for new or modified/modernized service interchanges dating

back to fiscal year 2007, at about seven annually.1 Traffic safety was not evaluated as a benefit relative

to diamond performance, even though it is.

22

Calculations

Benefits calculated are savings in interchange construction costs and road user costs. User travel time

is not a direct benefit to the agency so its effect on the return on investment will be separated from

agency construction cost savings. The below table was developed by Brad Steckler, INDOT Director of

Traffic Engineering for the purpose of this report.1

All the costs and benefits are discounted to 2017 dollars. The annual average savings for the seven year

period (2017- 2023) is based on an average of five interchange projects per year.

Potential Savings

• Lower construction costs

• Reduced user travel time through the interchange

• Reduced crashes resulting in safety benefits (not included in the analysis)

Below is the benefit cost analysis for a seven-year work plan provided by INDOT Traffic Engineering.

Estimated Interchange Construction Cost Savings1

Project Benefits and Costs $ FY 2017 FY 2018 FY 2019 FY 2020 FY 2021 FY 2022 FY 2023


Annual Construction Cost

Benefit 300,000 8,300,000 6,400,000 7,700,000 2,100,000 0

3,100,000

Net Benefit-Cost 147,000 8,300,000 6,400,000 7,700,000 2,100,000 0

3,100,000

NPV 27,747,000

Agency Benefits Cost Ratio 181

Fiscal Year of

Construction

Letting

# of

Diamond

Interchanges

Initial Capital

Construction

Investment Agency

Benefit (2017$)

Service Life

User Travel

Time Benefit

(2017$)

Sum of

Agency &

User Benefits

(2017$)

2017 5 $300,000 $2,100,000 $2,400,000

2018 9 $8,300,000 $2,500,000 $10,800,000

2019 5 $6,400,000 $1,600,000 $8,000,000

2020 9 $7,700,000 $3,300,000 $11,000,000

2021 2 $2,100,000 $700,000 $2,800,000

2022 0 None are planned 0 0

2023 6 $2,000,000 $1,200,000 $3,100,000

Total

2017--2023 36 $26,700,000 $11,400,000 $38,100,000

Annual Average

2017--2023 5 $4,500,000 $1,900,000 $6,400,000

23

Estimated User Cost Benefit1

Project Benefits and Costs $ FY 2017 FY 2018 FY 2019 FY 2020 FY 2021 FY 2022 FY 2023


Annual User Cost Benefit 2,100,000 2,500,000 1,600,000 3,300,000 700,000 0 1,200,000

Net Benefit-Cost 1,947,000 2,500,000 1,600,000 3,300,000 700,000 0 1,200,000

NPV 11,247,000

User Benefits Cost Ratio 74

Summary

The Agency benefit cost ratio for this project is 181 to 1. The estimated user benefit due to reduced

travel time is 74 to 1. These numbers are based on the following:


• User travel cost savings is $12/hr. for passenger cars and $25/hr. for commercial vehicles.1



Benefits from this research investment will continue into the future and return benefits many times

over.



References

1 Brad Steckler, INDOT Director of Traffic Engineering

Tarko, A. P., Romero, M. A., & Sultana, A. (2017). Performance of alternative diamond interchange

forms: Volume 1—

Research report (Joint Transportation

Research Program Publication No. FHWA/IN/JTRP-2017 /01). West Lafayette,

IN: Purdue University. https://doi.org /10.5703/1288284316385

Tarko, A. P., Romero, M. A., & Sultana, A. (2017). Performance of alternative diamond interchange

forms: Volume 2—

Guidelines for selecting alternative diamond interchanges (Joint Transportation

Research Program Publication No.

FHWA/IN/JTRP-2017 /02). West Lafayette, IN: Purdue University. https://doi.org

/10.5703/1288284316386

INDOT Research Program Benefit Cost Analysis – Return on Investment

For Projects completed in FY 2016

(SPR – 4225)

This Annual Return on Investment (ROI) Report for the INDOT Research Program was prepared

at the request of the Governor’s Office and INDOT Executive Staff

Bob McCullouch PE, Ph.D.

School of Civil Engineering

Purdue University

December 2017

(Amended August 2018)

1

Table of Contents

Introduction ..................................................................................................................................................... 1

Benefit-Cost Analysis Methodology ................................................................................................................. 1

Benefit-Cost Analysis Results ........................................................................................................................... 2

Summary .......................................................................................................................................................... 8

Appendix .......................................................................................................................................................... 9

Individual Project Analysis ................................................................................................................ 13

SPR-2938: Materials Characterization for the AASHTO New Design Guide ..................................... 13

SPR -3403: Removing Obstacles for Pavement Cost Reduction by Examining Early Age Opening

Requirements……………………………………………………………………………………………………………………………….16

SPR-3418: Quantifications of Benefits of Subsurface Drainage……………………………………………………..18

SPR-3506: Concrete Pavement Joint Deterioration……………………………………………………………………….21

SPR-3510: Subbase Requirements for Utilizing Unsealed Joints in PCCP……………………………………….24

SPR-3617: Bridge Preservation Treatments and Best Practices……………………………………………………..26

SPR-3624: Optimizing Laboratory Mixture Design as it Relates to Field Compaction in order to

Improve Hot-Mix Asphalt Durability………………………………………………………………………………………………28

SPR-3636: LRFD of Bridge Foundations Accounting for Pile Group-Soil Interaction……………………….31

SPR-3705: Performance Assessment of Road Barriers in Indiana…………………………………………………..34

SPR-3830: Evaluation of Alternative Intersections and Interchanges…………………………………………….37

List of Tables

Table 1. Quantitative Benefits Projects List ……………………………………………….……………….…………………………..2

Table 2. Agency Savings Projects Five-Year Cash Flows…………………………………………………………………………….5

Table 3. Safety/RUC Savings Projects Five-Year Cash Flows …………………………………….………………………7

Table 4. Complete Research Project List – FY 2016…………………………………………………….………………………9

2

Introduction

The Governor’s Office requested an annual financial analysis of the INDOT Research Program to

determine the return on the research investment (ROI). The current financial analysis is for research

projects that completed in FY 2016. Analyses on previous year’s projects is necessary primarily due to

the time it takes some project outcomes to be implemented goes into the following year, so FY 2016

analysis is done in 2017. This analysis will supplement the annual IMPACT report (qualitative and

quantitative benefits) by adding a more rigorous quantitative benefit cost analysis (BCA) to the Research

Program. Previous financial analyses used the approach of calculating net present values of cash flows

to determine a benefit cost ratio and this report uses the same approach. Additionally, an overall

program rate of return (ROI) is reported and will be accumulated over time into a rolling 5-year average.

While the quantitative benefit cost analysis (BCA) was rigorous, results are limited to projects where

benefits and costs could be quantified. Qualitative benefits are highlighted in the companion annual

IMPACT report ( https://www.in.gov/indot/files/FY 2017 Research Program IMPACT Report.pdf).

Benefit-Cost Analysis Methodology

All FY 2016 completed projects were reviewed to determine if it is a viable candidate for BCA. Selection

was based on 1) can the costs and benefits be quantified on outcomes that impact INDOT operations, 2)

what are the implementation costs, and 3) what is the expected impact time period?

The ROI analysis included the following savings components:

o Agency savings and costs. This was based on research findings, engineering

judgment/estimates from INDOT BO (business owner) and SME (subject matter

experts), available data, and projected use of the new product/process.

o Road User Costs (RUC) Savings. RUC includes value of time (VOT), and vehicle operating

costs (VOC). RUC unit values will be obtained from current INDOT standards which

INDOT provided.

o Safety Costs (SC) Savings. Safety costs (SC) can include a before and after evaluation or

engineering judgement from BO/SMEs to calculate the reduction in crashes (e.g.

property damage, fatalities, etc.). SC unit values will be obtained from current INDOT

standards which INDOT provided.

Accrued Benefits will be the combination of Agency savings, RUC cost savings, and SC savings. While

Road User Cost (RUC) savings and Safety Cost (SC) savings are a primary goal of INDOT, savings accrued

primarily benefit the customer (road user) and may not result in agency cost savings, and in some cases

may increase agency costs. For this reason, B/C is separated into two categories, Agency Savings and

Safety/RUC Savings. Safety and RUC savings are often related, these savings were combined into the

same category.

Quantitative benefits were calculated for each research project analyzed for the expected impact period

where known or planned quantities (estimated in the INDOT 5-year work program) were available. A

five-year analysis period was used on eight of the ten projects while a 24 and 75 year periods used on

two others, which are explained in their individual analysis. Individual project costs are research and

implementation costs. Net present value (NPV) for individual projects are calculated to 2016 dollars by

combining costs and benefit cash flows. Individual project analyses are included in the Appendix.

3

Backup documentation describing calculations and analysis for qualifying projects will be kept by the

INDOT Research Division and are available for review.

The ROI is expressed as a BCA ratio, which is commonly used by State DOTs and national transportation

research agencies when expressing the return on the research investment. This methodology will be

used annually to calculate a FY ROI which will be combined with other FY ROI to create a rolling average

over time. The rolling average will accumulate up to a maximum of the five recent years, with FY 2016

being the first year.

Benefit-Cost Analysis Results

Project outcomes were classified as either Quantitative, Qualitative, or Not Successfully Implemented.

• Quantitative - Implementation produces benefits that are measureable and quantifiable. Each

of these projects has an individual analysis performed and is included in the Appendix. The

analysis or impact period is the time benefits were calculated.

• Qualitative - Implementation is successful and benefits occur, but cannot be quantified with

certainty due to data not being available or easily discoverable. Examples of qualitative benefits

could include a specification revision, a proof-of-concept study, a synthesis study that produces

a summary of options and best practices, manuals or guidelines, or where cost comparison data

is unavailable.

• Not Successfully Implemented - For various reasons the project outcomes could not be

currently implemented. Common reasons are management, logistical, technical, or legal issues.


Table 1 is the list of the ten projects where benefits (NPV 2016$ - NPV of future cash flows in 2016

dollars) could be quantified and their individual analysis is found in the Appendix. Table 2, in the

Appendix, is a complete list of all 42 projects completed in FY 2016.

Table 1. Quantitative Benefits Project List

No

FY 16 Completed & Implemented

SPR Projects

Project Cost TITLE Benefit Type

Analysis

Period

NPV Project Benefit ($1000)

2016$

($1000)

1 2938 $150

Materials Characterization for the AASHTO New

Design Guide


4

2 3403 $250

Removing Obstacles for Pavement Cost

Reduction by Examining Early Age

Opening Requirements


3 3418 $97 Quantifications of

Benefits of Subsurface Drainage


4 3506 $240 Concrete Pavement Joint Deterioration

Agency Savings 5 Years $544

5 3510 $100

Subbase Requirements for Utilizing Unsealed

Joints in PCCP


6 3617 $100 Bridge Preservation Treatments and Best

Practices Agency Savings 75 Years $11,481

7 3624 $204

Optimizing Laboratory Mixture Design as it

Relates to Field Compaction in order to Improve Hot-Mix Asphalt Durability


8 3636 $416

LRFD of Bridge Foundations

Accounting for Pile Group-Soil Interaction


9 3705 $150 Performance

Assessment of Road Barriers in Indiana

Safety/RUC Savings 24 Years $273,714

10 3830 $235

Evaluation of Alternative

Intersections and Interchanges

Safety/RUC Savings 5 Years $17,029

Total Benefits $367,224

Eight of the projects have a five-year analysis period. On these projects the annual benefits were based

on planned installed quantities that resulted in immediate savings, such as construction cost savings.

Project 3617 analysis period is based on the expected bridge life of 75 years, because the recommended

maintenance program starts after construction and is in place throughout the life of the bridge. Project

3705 has a 24 - year analysis period because it uses barrier quantities estimated in the 5-year work plan

and maintenance and user safety costs calculated during the 20-year barrier life.

5

Agency Savings

The total quantifiable savings from the eight projects resulting in agency savings, during their analysis or

impact period, was calculated at $76,481,000 (in 2016$). The total research program cost in FY 2016

was $6,264,000. Therefore, the agency savings BCA for FY 2016 is: $76,481,000/$6,264,000 = 12, or 12

dollars in agency savings for every research dollar expended.

Safety/RUC Savings

The total quantifiable savings from the two projects resulting in safety/RUC savings, during their analysis

or impact period was calculated at $290,743,000 (in 2016$). The total research program cost in FY 2016

was $6,264,000. Therefore, the safety/RUC savings BCA for FY 2016 is: $290,743,799/$6,264,000 = 46,

or 46 dollars in safety/RUC savings to our customers for every research dollar expended.

A table for each savings category was created, eight projects cash flows classified as Agency Savings

(Table 2) and two projects classified as Safety/RUC Savings (Table 3). A condensed version of the tables

are shown. The expanded version of each table cannot be incorporated into the report due to its size,

but are provided as supplementary files.

Table 2. Agency Savings Projects Five -Year Cash Flows

Project Description FY2016 FY2017 FY2018 FY2019 FY2020 FY2021


impact)* 0

11,569,300 7,424,500 6,183,700 6,051,700 5,814,100


cost -150,000

Net benefit -150,000 11,569,300 7,424,500 6,183,700 6,051,700 5,814,100

NPV FY 2016 33,137,617


impact)*

1,248,750 1,286,213 1,324,799 1,364,543 1,405,479


cost -250,000

Net benefit -250,000 1,248,750 1,286,213 1,324,799 1,364,543 1,405,479

NPV FY 2016 5,642,615


impact)*

960,000 960,000 960,000 960,000 960,000


cost -97,000

Net Benefit -97,000 960,000 960,000 960,000 960,000 960,000

NPV FY 2016 4,174,290

3506 - Annual Benefits (5 year

impact)* 0

165,000 169,950 175,049 180,300 185,709


cost -240,000

Net Benefit -240,000 165,000 169,950 175,049 180,300 185,709

6

NPV FY 2016 544,632


impact)*

1,457,533 1,501,259 1,546,297 1,592,686 1,640,466


cost -100,000

Net Benefit -100,000 1,457,533 1,501,259 1,546,297 1,592,686 1,640,466

NPV FY 2016 6,772,236

3617 - Benefit, 75 year life (1)


cost -100,000

Net Benefit -100,000 390,627 390,627 390,627 390,627 390,627

NPV FY 2016 11,481,000


impact)*

5,005,440 1,689,600 696,960 591,360 401,280


cost -204,000

Net Benefit -204,000 5,005,440 1,689,600 696,960 591,360 401,280

NPV FY 2016 7,531,690


impact)*

1,613,355 1,661,756 1,711,608 1,762,957 1,815,845


cost -416,000

Net Benefit -416,000 1,613,355 1,661,756 1,711,608 1,762,957 1,815,845

NPV 2016 7,199,826

NPV Total 2016 $

76,483,906





Program

1. The first 5 years of the 75 year cash flows are shown. See supplementary file for the


7

Table 3. Safety/RUC Savings Projects Five-Year Cash Flows

Project Description

3705 - 24 year life (1) FY2016 FY2017 FY2018 FY2019 FY2020 FY2021


cost -150,000

Barrier Cost - INDOT 5 Year

program* -4,800,000 -4,944,000 -5,092,320 -5,245,090 -5,402,442

Annual Maintenance Cost -120,000 -247,200 -381,924 -524,509 -675,305

Annual Benefit -2016

installation 3,200,000 3,296,000 3,394,880 3,496,726 3,601,628

Annual Benefit 2017

installation 3,296,000 3,394,880 3,496,726 3,601,628

Annual Benefit 2018

installation 3,394,880 3,496,726 3,601,628

Annual Benefit 2019

installation 3,496,726 3,601,628

Annual Benefit 2020

installation 3,601,640

Net Benefit-Cost -4,950,000 -1,864,000 1,252,480 4,557,626 8,059,954 17,332,847

NPV 2016 273,714,281


impact)*

1,692,000 2,820,000 3,948,000 5,076,000 6,204,000


cost -235,000

Net Benefit -235,000 1,692,000 2,820,000 3,948,000 5,076,000 6,204,000

NPV 2016 $

17,029,518

NPV Total 2016

290,743,799





Program

1. The first five years of the 24 year cash flows are shown. See supplementary file for the


Eight of the ten projects, with quantifiable benefits, resulted in agency savings, while two other projects

resulted in a reduced Safety and Road User Cost (RUC). A summary of these cost savings are described

below.

8

• 2938 – New pavement design procedure reduces asphalt pavement thickness on mainline

pavements by 1.5” and concrete pavements greater than 12” thick by 1.5”. The savings are

lower pavement material costs.

• 3403 - Allows for a reduction in cement values for concrete pavements and an earlier opening

date to traffic. Savings are lower concrete pavement costs.

• 3418 - A proper subsurface drainage layer below heavily traffic areas can improve pavement life.

Benefit is longer pavement life in these areas.

• 3506 – A new concrete pavement joint design for transverse joints reduces material and

construction costs.

• 3510 – Revising concrete pavement joint detail results in construction cost savings.

• 3617 – A new bridge deck maintenance program reduces life cycle costs in its maintenance and

upkeep.

• 3624 – Changing asphalt pavement mix design increases pavement life and reduces pavement

lifecycle costs of asphalt pavements.

• 3636 – A new pile driving formula results in higher pile capacities, lower pile quantities and

lower pile costs.

• 3705 - Installing median cable barrier systems is more cost-effective than other barrier options

due to lower maintenance and user safety costs.

• 3830 project benefits are classified as Road User Costs (RUC) as the Double Diamond

Interchange option reduces travel time through the intersection.

Summary

The aggregate benefit is significant, resulting in more than $367 million in savings over the projected

service lives (in 2016$). The aggregate combines agency savings and expected savings for users of the

INDOT network. Direct agency savings of over $76 million is a return of $12 for every $1 spent in

research. For users the return is 46 to 1 through improved safety and lower user costs. The basis for

the numbers used in the BCA came from INDOT personnel, Industry Associations, and researchers.

These are described in detail in the individual analyses located in the Appendix.

A ROI of 12 to 1 is considered an outstanding agency return on research investment. While the ROI is

significant, a review of the individual project analysis shows a conservative approach was taken in any

assumption made and in the calculations, and actual savings may be much higher. This analysis

indicates that INDOT is receiving a significant return on its research investment which will continue to

grow due to recently passed legislation (HB 1002), authorizing more funding for construction, re-

construction, and preservation.

For 29 projects completed in FY 2016, quantifiable benefits could not be calculated, however other

qualitative benefits resulted that brought significant value to the Department and are highlighted in the

annual IMPACT report. Ten of the projects were quantified and described herein, and three of the

projects were not successfully implemented due to various reasons. A complete listing of research

projects completed in FY 2016 is shown in Table 4 in the Appendix.

9

Appendix

Table 4. – Complete Research Project List – FY 2016

No

FY 16 Completed & Implmented

SPR Projects

Project Title Project

Cost ($ 1000)

Quantitative Benefits,

Qualitative Benefits or Not Successfully Implemented

Project Benefits ($1000)

1 2938 Materials Characterization for the AASHTO New Design Guide

$150

33137

2 3403

Removing Obstacles for Pavement Cost Reduction by Examining Early Age Opening Requirements

$250

5643

3 3418 Quantification of Benefits of Subsurface Drainage

$97

4174

4 3425 Improved Methods of Bridge Maintenance and Inspection

$75 Not

Successfully Implemented

0

5 3506 Concrete Pavement Joint Deterioration

$240

757

6 3510 Subbase Requirements for Utilizing Unsealed Joints in PCCP

$100

6772

7 3512 Performance Evaluation of Deployed Cathodic Protection

$100 Qualitative

Benefits 0

8 3523

Evaluation of Sealers and Waterproofers for Extending the Life Cycle of Concrete

$150 Qualitative

Benefits 0

9 3533

Performance Evaluation of Crack Sealing and Filling Materials with Pavement Preservation Treatments

$118 Qualitative

Benefits 0

10 3615 Active Corridor Management

$500 Qualitative

Benefits 0

11 3617 Bridge Preservation Treatments and Best Practices

$100

11581

10

12 3624

Optimizing Laboratory Mixture Design as it Relates to Field Compaction in order to Improve Hot-Mix Asphalt Durability

$204

7531

13 3626

Enhanced Treatment Selection for Reflective Joint Cracking in Composite Pavements

$169 Qualitative

Benefits 0

14 3630

Efficient Load Rating an Quantification of Life-Cycle Damage of Indiana Bridges for Overweight Loads

$173 Qualitative

Benefits 0

15 3636

LRFD of Bridge Foundations Accounting for Pile Group-Soil Interaction

$416

7199

16 3704

Indiana State Highway Cost Allocation and Revenue Attribution Study / Estimation of Travel by Out-of-State Vehicles on Indiana Highways

$375 Qualitative

Benefits 0

17 3705 Performance Assessment of Road Barriers in Indiana

$150

273714

18 3706

Laser Mobile Mapping Standards and Applications in Transportation

$234 Qualitative

Benefits 0

19 3707

A Synthesis Study on Collecting, Managing, and Sharing Road Construction Asset Data

$145 Qualitative

Benefits 0

20 3716 Relating Design Storm Events to Ordinary High Water Marks in Indiana

$125 Qualitative

Benefits 0

21 3717 Streambank Stabilization Alternatives to Riprap

$108 Qualitative

Benefits 0

22 3726 Upgrading RoadHAT - Collision Diagram Builder and HSM Elements

$165 Qualitative

Benefits 0

23 3751

Evaluation of the Microstructural Characteristics of Soil Treated with Cement Kiln Dust (CKD) and Used as a Subgrade at US 24

$33 Qualitative

Benefits 0

11

24 3800

Development of a Geographic Winter-Weather Severity Index for the Assessment of Maintenance Performance

$175 Qualitative

Benefits 0

25 3802

Development of Standardized Component Based Equipment Specifications and Transition Plan Into a Predictive Maintenance Strategy.

$115 Qualitative

Benefits 0

26 3805 Long Term Pavement Performance Indicators for Failed Materials

$140 Qualitative

Benefits 0

27 3806

Verification of the Enhanced Integrated Climatic Module Soil Subgrade Input Parameters in the MEPDG

$132 Qualitative

Benefits 0

28 3810

Analysis of the MSCR Asphalt Binder Test and Specifications for Use in Indiana

$210 Qualitative

Benefits 0

29 3813

Performance of Warranted Asphalt Pavements: Smoothness and Performance of Indiana Warranted Asphalt Pavements

$120 Qualitative

Benefits 0

30 3819

Element Level Bridge Inspection - Benefits and Use of Data for Bridge Management

$69 Qualitative

Benefits 0

31 3828 Models to Support Bridge Management

$125 Qualitative

Benefits 0

32 3829

Estimation and Prediction of Statewide Annual VMT by Vehicle Class and Highway Category

$100 Qualitative

Benefits 0

33 3830 Evaluation of Alternative Intersections and Interchanges

$235

17029

34 3856

INDOT-JTRP Project/Program Implementation Improvement

$102 Qualitative

Benefits 0

12

35 3859 Culvert Inspection and Data Management

$25 Qualitative

Benefits 0

36 3863 Use of Tablets and Apps to Enhance Construction Inspection Practices

$165 Qualitative

Benefits 0

37 3864 Performance of Deicing Salts and Deicing Salt Cocktails

$85 Qualitative

Benefits 0

38 3901

Synthesis Study: Best Practices for Maximizing Driver Attention to Work Zone Warning Signs (End of Queue Warning Devices)

$45 Qualitative

Benefits 0

39 3907 Simplified Construction Scheduling for Field Personnel

$85 Not


0

40 3908 Algorithm and Software for Proactive Pothole Repair

$78 Qualitative

Benefits 0

41 3941 Storm Water Pollution and Best Management Practice Guidance for Indiana

$36 Not


0

42 3944 Pre-Contract Scoping Processes – Synthesis of Best Practices

$46 Qualitative

Benefits 0

13


SPR-2938: Materials Characterization for the AASHTO New Design Guide

Introduction

The Mechanistic-Empirical Pavement Design Guide (MEPDG) developed under NCHRP Project 1-37A and

adopted by AASHTO presents a new paradigm of pavement design and analysis. The Guide considers

the input parameters that influence performance, including traffic, climate, and pavement layer

thickness and properties and applies the principles of engineering mechanics to predict critical

pavement responses. Not only does the MEPDG change the process and design inputs, it also changes

the way engineers think and implement strategies for more effective and efficient pavement design.

The Indiana Department of Transportation (INDOT) began implementation of the MEPDG on January 1,

2009. This project looks at the impact of its implementation and calculates its impact on projects

starting in 2017.

Analysis

In the period January to December 2009, INDOT staff and consultants designed more than 100

pavement sections using the MEPDG procedure. As required by the FHWA Indiana Division for

implementation of MEPDG, INDOT documented the pavement thickness design of all new pavements

and provided comparisons of the thicknesses estimated using the AASHTO 1993 Guide for Design of

Pavement Structures to those estimated using the MEPDG procedures. 2 In addition, the INDOT

Executive Staff reviewed the cost savings attributed to the “more efficient” pavement designs provided

by the MEPDG. Estimated cost savings are based on reducing asphalt base courses by 1.5” and concrete

pavements 12” or greater by 1.5” inches. Savings will occur on mainline pavements and the below

calculations are based on this. Overlay projects are not impacted.

Calculations

Savings calculations are broken into concrete and asphalt pavements.

Concrete

Based on quantities reported by the concrete paving industry3, in 2016 and 2017 approximately

1,500,000 square yards (SY) of concrete pavement was placed. When pavements were greater than

12” thick, then the thickness could be reduced by 1.5”. It is anticipated the same amount of concrete

pavement will be placed between 2018 – 2021. 3

Based on average concrete bid costs the cubic yards (CY) cost varies from $85 (from on-site batch plant)

to $115 (purchased from supplier). Assuming concrete comes from an on-site batch plant (conservative

assumption), then the material savings from reducing thickness by 1.5” was calculated as follows:

1,500,000 SY x 9 SF/SY x 1.5”/12” = 1,687,500 cubic feet (CF) of concrete reduced = 1,687,500/27 =

62,500 CY of concrete materials saved. Labor and equipment costs are minimally affected by less

material quantity since the area (SY) of pavement does not change.

14

Annual concrete material saving = 62,500 CY x $85/CY = $5,312,500

Asphalt

Mainline asphalt quantities were obtained from INDOT records for current year projects and planned

projects for the years 2018 – 2021.4 237 lane miles of asphalt pavement were placed in 2017. Base

course thickness reduction was 1.5”.

Forecasted estimated mainline lane miles of asphalt pavement.4

2018 2019 2020 2021

80 33 28 19

Reduced thickness of 1.5” occurs in the base course. In 2017 base course material average cost was

$50/ton.

Base Course Material Savings per Year

Base course weighs 100#/SY/in.

CY 2017

Pavement area = 237 lane miles x 5,280 ft./mile x 12’ (lane width) x 1 SY/9SF = 1,668,480 SY

Weight savings = 1,668,480 SY x 1.5”(thickness reduction) x 100#/SY/in. x 1 ton/2000 # = 125,136 tons

Cost savings = 125,136 tons x $50/ton = $6,256,800

CY 2018

Pavement area = 80 lane miles x 5,280 ft./mile x 12’ (lane width) x 1 SY/9SF = 563,200 SY

Weight savings = 563,200SY x 1.5”(thickness reduction) x 100#/SY/in. x 1 ton/2000 # = 42,240 tons

Cost savings = 42,240 tons x $50/ton = $2,112,000

CY 2019

Pavement area = 33 lane miles x 5,280 x 12’ x 1 SY/9SF = 232,320 SY

Weight savings = 232,320 x 1.5” x 100#/SY/in. x 1 ton/2000# = 17,424 tons

Cost Savings = 17,424 tons x $50/ton = $871,200

CY 2020

Pavement area = 28 lane miles x 5,280 x 12’ x 1/9 = 197,120 SY

Weight savings = 197,120 x 1.5” x 100#/SY/in. x 1 ton/2000# = 14,784 tons


CY 2021

Pavement area = 19 lane miles x 5,280 x 12’ x 1/9 = 133,760 SY

15

Weight savings = 133,760 x 1.5” x 100 x 1/2000 = 10,032 tons


These annual costs savings are calculated from asphalt base course material savings due to thickness

reduction in pavement. Due to the variability in future concrete and asphalt prices, the average cost of

concrete and asphalt in 2017$ was used, which are $85/CY and $50/ton, respectively.

The financial analysis takes a present worth approach for a five-year period with expected capital cost of

3%. No inflation was used in concrete or asphalt cost. The five-year period coincides with an INDOT

proposed 5-year work plan which estimates expected pavement quantities. Benefits are expected to

accrue after the 5-year period, but are not calculated as pavement quantities are unknown. Annual

benefit numbers in the below table are combined for concrete and asphalt.

Project Benefits and Costs FY 2016 FY 2017 FY 2018 FY 2019 FY 2020 FY 2021


Annual Benefit 11,569,300 7,424,500 6,183,700 6,051,700 5,814,100

Net Benefit-Cost -150,000 11,569,300 7,424,500 6,183,700 6,051,700 5,814,100

NPV $33,137,617.19


Summary



• 5 Year work program scheduling pavement estimates were used.

• Concrete cost of $85/CY and asphalt cost of $50/ton



The overall 2016 benefit cost analysis is based on total program costs. This analysis is for this project’s

cost to execute the research and implement.

References

1 Pavement Cost Study by John Weaver, INDOT Statewide Asset Management Engineer, April 2017.

2 The Mechanistic-Empirical Pavement Design Guide: A tool for Cost Savings, Tommy Nantung, INDOT

Manager of Pavements, Materials, and Construction Research, INDOT Research Division.

3 Cost, project, and estimated quantity data were provided by Mike Byers, Indiana Ready Mix Concrete

Association.

4 Quantities provided by John Weaver and Andrew Pangallo, INDOT Field Engineer,

[email protected].

16

SPR-3403: Removing Obstacles for Pavement Cost Reduction by Examining Early Age Opening

Requirements

Introduction

This project produced a special provision for early opening to traffic on concrete pavements. Through

accelerated testing at the APT lab in the Research Division, test results indicate long term performance is

not impacted, at certain thicknesses, with early opening as tensile stresses are lower than expected.

With lower actual tensile stresses, lower strength concrete can be used, allowing a reduction of cement

quantities in concrete.

Analysis

The basis of the cost benefit analysis is the reduction in cement requirements for a cubic yard of

concrete by allowing its strength to reduce form 500 psi to 425 psi. This strength reduction saves

approximately 50 lbs. of cement per cubic yard of concrete. At current cement prices this saves

approximately $2.50/cubic yard.1

Calculations

Research cost was $250,000. Indiana Ready Mix Concrete Association and Tommy Nantung, INDOT

R&D, provided data in the benefit cost analysis.

Potential Savings

With an estimated material savings in concrete of $2.50/cubic yard from cement reduction, the annual

cost savings calculations are:

• Average concrete pavement thickness is 12”.

• Using the average annual placement of concrete pavement at 1,500,000 SY*, the annual volume

of concrete placed is 1,500,000 SY x 12”/36” = 499,500 CY

• Annual cost savings = 499,500 x $2.50 = $1,248,750

• The financial analysis takes a present worth approach for the next five-year construction period

with expected capital cost and inflation of 3%.

Below is the benefit cost analysis for a five-year work plan.



Annual Benefit 1,248,750 1,286,213 1,324,799 1,364,543 1,405,479

Net Benefit-Cost -250,000 1,248,750 1,286,213 1,324,799 1,364,543 1,405,479

NPV $5,642,614.76


17

Summary



• 5 Year work program scheduling 1,500,000 SYS of concrete pavement annually.

• Cement savings of 50#/CY equates to a cost saving of $2.50/CY.





References

1Cost, project, and estimated quantity data were provided by Mike Byers, Indiana Ready Mix Concrete

Association and Tommy Nantung , INDOT Division of Research.

18

SPR-3418: Quantifications of Benefits of Subsurface Drainage

Introduction

Performance information available indicates properly designed and constructed

permeable bases virtually eliminate pumping, faulting, and cracking. A review of current

design and construction practices has proven permeable base pavements can be

designed and constructed to rapidly drain moisture that infiltrates the pavement surface.

Typical INDOT permeable base materials for asphalt pavement are asphalt open-graded aggregates and

concrete pavement unbound # 8 aggregates. The objectives of this project were to evaluate the

performance of current INDOT sub-drainage systems and to evaluate maintenance procedures for

existing edge drains and outlets. The study presents a comprehensive pavement performance

evaluation to determine the effectiveness of subsurface drainage in the following aspects: INDOT

existing materials specifications for permeable and filter layer, lab testing of subgrade materials due to

the moisture accumulation, numerical modeling of water infiltration into pavement, pavement distress

field survey, outlet spacing and maintenance inspection, and annual evaluation of pavement

performances and pavement structure strength.

The contribution of the positive subsurface drainage to the strength of the pavement can

be categorized in two ways: the improvement of the stiffness of the subgrade and the increase of HMA

(Hot Mix Asphalt) modulus to prevent stripping and cracking. Undrained pavement results in

approximately $40,000 to $60,000 more in (maintenance) costs for each lane-mile. Traffic can cause

significant differences in pavement life and heavy traffics, 30 million equivalent single axel loads

(MESALS) result in thickness differences between undrained and drained pavement, compared to that

under medium traffic (10 MESALs). This indicates that moisture under heavy traffic loading causes more

pavement damage than under light traffic.

Analysis

An estimated $40,000 to $60,000 per lane-mile can be saved at the traffic level of 10 to 30 MESALs if a

drainage layer is installed properly 1. Therefore, providing adequate drainage to a pavement system has

been considered an important design implementation to ensure satisfactory performance of the

pavement, particularly from the perspective of life cycle cost and serviceability.

Calculations

The cost analysis is based on the following:

• Proper subsurface drainage layers can extend pavement life and reduce damage particularly in

heavily traffic areas.

• Heavily traffic areas are those segments that experience 10-30 MESALs.

• When these segments are rebuilt, $40,000 - $60,000 (maintenance/capital cost?) per lane mile

in savings occur when a proper drainage layer is installed.

• Estimated maintenance savings are based on a projected five-year work plan for reconstructing

heavy traveled interstate sections.

MESAL data was provided by the INDOT GIS section 2. Below is a map showing where these segments

occur in the state.

19

These heavy traffic segments total to 5,600 lane miles 2.

Using the lower unit cost of $40,000 per lane mile, the following analysis is based on 120 lane miles to

be reconstructed over the next 5 years, according to the Next Level Roads Program. An average lane

mile of 1/5 per year, 120 x 1/5 = 24 is used.

20



Annual Benefit 960,000 960,000 960,000 960,000 960,000

Net Benefit-Cost -97,000 960,000 960,000 960,000 960,000 960,000

NPV $4,174,290.19


Summary

The benefit cost ratio is 43 to 1. This number is based on:

• Research cost is $97,000.

• Savings of $40,000 per lane mile for the next five years for a properly installed drainage system.

• Twenty-four lane miles, based on the Next Levels Five Year Road Program, are reconstructed

each year for the period, 2017-2021.

• No inflation factor applied.



References

1. Final Report # FHWA/IN/JTRP -2015/xx, Quantification of Benefits of Subsurface Drainage, Richard Ji,

Qi Qi.

2 MESAL data provided by Kevin Munro, Statewide GIS Asset Manager, INDOT.

21

SPR-3506: Concrete Pavement Joint Deterioration

Introduction

In recent years the number of reported joints deteriorating prematurely in concrete pavements around

Indiana has increased. Changes over the past 45 years in INDOT specifications, pavement materials and

design, construction practices, and deicing materials were examined related to the durability of concrete

joints in existing pavements.

This study identified that one or more of the following variables influenced the durability of the concrete

at joints examined: the draining ability of the base at the joints, original air void system, reduced air void

parameters due to lining and infilling of the air voids with secondary minerals, compromised hydration

of the concrete at the joint face, and increased moisture at the joint.

To combat increased moisture at the joint, a new joint detail was recommended to reduce the entry of

moisture into the joint.

Analysis

The basis of the cost benefit analysis is the savings in maintaining concrete pavements at the joints

resulting from a new joint design.

Calculations

Research cost was $240,000. The Indiana Ready Mix Concrete Association1 and Tommy Nantung,

INDOT R&D, provided data used in the benefit cost analysis. Tie bar requirements came from INDOT

Design Standards. 2

Estimated tie bar cost from contractor - #5 = $1.68 ea., #6 = $2.12 ea., #7 = $2.68 each

Concrete pavement panel size = 12’x 15’ = 180 square feet = 20 SY

SY – square yard, SYS – square yards

Concrete pavement 12” or thicker with transverse joints spaced 15’ on center bar requirements are:

a. Previous standard: concrete pavement w/ transverse joints spaced at 15’. At 3 ft.

spacing # of bars in a pavement panel = 15’/3’ = 5 spacings which is 4 bars. At 2 ft.

spacing # of bars in a pavement panel = 15’/2’ = 7 spacings which is 6 bars.

Longitudinal joint bars

#7 @ 3’ = 4 bars x $2.68 = $10.72/panel – $10.72/20 SY = $0.54/SY to cost of pavement

#6 @ 2’ = 6 bars x $2.12 = $12.72/panel – $12.72/20 SY = $0.64/SY to cost of pavement

b. New Standard for Joint Design: concrete pavement w/ transverse joints at 15 ft.

Longitudinal joint bars

#6 @ 3’ = 4 bars x $2.12 = $8.48/panel - $8.48/20 SY = $0.43/SY to cost of pavement

22

Estimated Savings:

Comparing bar options

#7(old standard) vs. #6 (new standard) - $0.54 - $0.43 = $0.11/SY

#6(old standard) vs. #6 (new standard) - $0.64 - $0.43 = $0.21/SY

For the last several construction seasons INDOT has placed on average of 1.5 million SYS of

concrete pavement. It is expected this quantity will continue in the next five-year construction

plan.

Estimated cost saving range in 2017 is:

$0.11 x 1,500,000 SYS = $165,000 (#7 vs. #6)

$0.21 x 1,500,000 SYS = $315,000 (#6 vs. #6)

Potential savings range is $165,000 to $315,000 in 2017. For the cost benefit analysis, the lower

number, $165,000, will be used, which is a conservative number, benefits could be higher.

Example project impact

1) On a SR 62 project (RS-35119) bid in April 2017 – there was 139,756 SF of partial depth joint

repair on a project with 272,754 SYS of pavement.

2) Bids were received from three contractors for the 139,746 SF of joint repair.

Contractor bid #1 - $26.15/SF = $3,654,819 – or $13.40/SY impact



Avg. = $14.90/SY – Cost to fix concrete joint damage

Average bid cost = $4,036,686

For this one project, the average repair cost to fix deteriorated joint damage is nearly $4 million. This

project illustrates how costly repairs can be. Going to a different joint design will mediate some of this

damage, but to say that all damage will be eliminated cannot be substantiated or used in cost benefit

calculations. Therefore, cost savings are calculated from construction bar savings alone, in the five-year

program.

The financial analysis utilized a present worth approach for a five-year period with expected capital cost

and inflation of 3%. The five-year period coincides with an INDOT proposed 5-year work plan which

estimates pavement quantities. Benefits are expected to accrue after the 5-year period, but are not

calculated as pavement quantities are unknown.

Following is the benefit cost analysis for the next five-year work plan.

23



Annual Benefit 2017

Installation 165,000 169,950 175,049 180,300 185,709

Net Benefit-Cost -240,000 165,000 169,950 175,049 180,300 185,709

NPV $544,631.92


Summary



• 5 Year work program scheduling 1,500,000 SYS of concrete pavement annually.

• Longitudinal joint uses #6 bar @ 3 ft. vs. #7 bar @ 3 ft.(previous).





References


Association.

2Tommy Nantung, Manager for Pavement, Materials, and Construction Research, Indiana Department of

Transportation, Division of Research and Development.

24

SPR-3510: Subbase Requirements for Utilizing Unsealed Joints in PCCP

Introduction

The primary objective of this study was to investigate the possible cost benefits that can be

achieved through the use of sealed and unsealed joints and various subbase treatments to extend

the pavement life, without compromising pavement performance. The second objective of this

study was to investigate the performance of sealed/unsealed joints on treated/untreated

permeable subbase test sections.

Six concrete test pavement segments were constructed on US-24 with different types of subbases

and separation materials, and sealed and unsealed joints. The overall performance of the unsealed

joints was marginally better than the sealed joints in the pavement survey. Test sections 0 and 1

exhibited similar performance for unsealed joints on the same permeable subbase. Sections 3 and

4, which had higher construction costs, performed overwhelmingly better. The research concluded

that using unsealed joints can be a good practice with its low maintenance cost.

Analysis

The basis of the cost benefit analysis is the elimination of the second cut, backer rod, and sealant in

transverse joints.

Calculations

Research cost was $100,000. Indiana Ready Mix Concrete Association and Tommy Nantung, R&D,

provided cost and quantity data used in the analysis1,2.

Potential Savings

Based on contractor bids1, it is costing approximately $9.55/ft.* to install transverse joints in concrete

pavements. This project recommended modifying the joint by eliminating the second joint cut, backer

rod, and joint sealant. Concrete paving contractors estimate, with this modification, a savings of 17% in

joint cost is possible2. This equates to a saving of $1.62/ft.

Concrete pavements are typically 12 ft. wide with transverse joints spaced at 15 ft. on center. A lane

mile of pavement is 7,040 SY. Based on current and recent year concrete pavement quantities, INDOT is

placing on average approximately 1,500,000 SY of concrete pavement1. The linear feet of transverse

joint then is calculated to be:

• Number of transverse joints in a lane mile of pavement = 5,280/12 = 352 joints

• Number of lane miles in 1,500,000 SY of pavement = 1,500,000/7040 = 213 lane miles

• Annual linear feet of transverse joints = 352 x 213 x 12 ft. = 899,712 ft.

• Projected annual savings = $1.62/ft. x 899,712 ft. = $1,457,533

The financial analysis takes a present worth approach for a five-year period with expected capital cost


25

estimates expected pavement quantities. Benefits are expected to accrue after the 5-year period, but

are not calculated as pavement quantities are unknown.




Annual Benefit 1,457,533 1,501,259 1,546,297 1,592,686 1,640,466

Net Benefit-Cost -100,000 1,457,533 1,501,259 1,546,297 1,592,686 1,640,466

NPV $6,772,235.84


Summary



• 5 Year work program, scheduling 1,500,000 SYS of concrete pavement annually.

• Transverse joint saving is $1.62/ft.





References


Association.

2 Tommy Nantung, Manager for Pavement, Materials, and Construction Research, Indiana Department

of Transportation, Division of Research and Development.

26

SPR-3617: Bridge Preservation Treatments and Best Practices

Introduction

This project reviewed bridge maintenance activities recommended by current literature and to examine

those maintenance activities conducted by the Indiana Department of Transportation (INDOT) districts,

as well as maintenance activities performed by other DOT agencies. This review created a list of ten

bridge preventive maintenance activities that improve the effectiveness of bridge maintenance

operations in Indiana. The required conditions and frequency to perform each activity was analyzed, and

the cost and benefit of such operations was studied to ensure that the proposed activities are

economically feasible and sustainable. Based upon the analysis, all ten preventative maintenance

activities were found to be cost effective and are recommended as an effective means of bridge

preservation. The recommended ten maintenance activities are:

1. Bridge deck cleaning and washing

2. Bridge concrete deck maintenance. Repeat this procedure every five years.

3. Bridge joints

4. Bridge Bearings

5. Bridge approach slab

6. Superstructure cleaning and washing

7. Spot painting

8. Vegetation control

9. Removing debris from piers/abutments

10. Pin and hanger connection maintenance

Analysis

The project reported a life cycle cost analysis for deck maintenance, item 2 in the list. The other nine

maintenance activities are difficult to quantify savings. So the basis of the cost benefit analysis is to

calculate savings from implementing a deck preventative maintenance program.

Calculations

Research cost was $100,000. The square foot costs for four different deck maintenance options were

created in the final report and are based on information provided by INDOT. For each option a NPV was

calculated based on a bridge service life of 75 years; a discount rate of 4%; and a salvage value of $0 at

the end of the service life. These four option are:

1. Current INDOT Policy, no routine deck maintenance activities, PV (cost) = $80.63/SF

2. Sealing every 5 years and overlay at 35 years, PV(cost) = $43.30/SF

3. Sealing every 5 years, patching at 10 years, Overlay at year 35, PV(costs) = $48.18/SF

4. Sealing every 5 years, overlay at year 30, replace deck at year 50, PV(costs) = $59.96

Option 2 has the lowest annual cost for the bridge deck life of a new bridge. The estimated cost savings

is the cost difference between options 1 and 2, which is the estimated annual savings from using option

2 over the current INDOT approach.

• Estimated annual savings = $80.63 - $43.30 = $37.33/SF

• $37/SF during the 75-year deck life is used in the calculations.

27

• Since future deck quantities are difficult to estimate, an average of past year new bridge deck

quantities is used in the calculations.2 In the years 2013-2017 there were a considerable number

of new bridges built on the new I-69 segments, US 31, SR 25 (Hoosier Heartland), I-65 southern

Indiana, and the Ohio River bridges. With the increased funding provided in the last two

legislative sessions through HB 1001 and 1002, new bridges will be constructed, but likely not at

the same level experienced in the 2013-2017 time period. Since the Ohio river bridges have

very large decks and are not built every year, their quantities were not included. Deck

quantities for the I-69 bridges were removed as well. This produces a conservative cost savings

number.

• Average annual deck area for new bridges (2013-2017) = 313,000 SF

• Average cost savings for a new bridge (75-year life) using option 2 maintenance plan is:

313,000 SF * $37.33/SF = $11,581,000 (one year of new bridges constructed)

• NPV Benefits (75 years) = $11,581,000

Convert to annual benefits for 75 years = $11,581,000 (A/P @ 3%)

Annual cash flow benefit = $11,581,000 * .03373 = $390,627, annual cash flow, see table

• Benefit cost ratio = $11,581,000/ $100,000 = 115.81

Summary





References

1 Bowman, M. D., & Moran, L. M. (2015). Bridge preservation treatments and best practices (Joint

Transportation Research Program Publication No. FHWA/IN/JTRP-2015/22). West Lafayette, IN: Purdue

University. https://doi.org/10.5703/1288284316007.

2 Bridge deck quantities provided by Jaffar G. Golkhajeh, Bridge Asset Management Office, Division of

Bridges, INDOT. Email: [email protected]. Bridges where deck or superstructure were replaced,

deck areas came from SPMS. Existing bridges which were replaced or built on new alignments came

from the Bridge Inspection Application System (BIAS).

28

SPR- 3624: Optimizing Laboratory Mixture Design as it Relates to Field Compaction in order to

Improve Hot-Mix Asphalt Durability

Introduction

The objective of the research was to optimize asphalt mixture laboratory design compaction as

it relates to field compaction in order to increase asphalt pavement durability, without

sacrificing the permanent deformation characteristics of the mixtures. INDOT’s current asphalt

mixture design method specifies a design air voids content of 4 percent. Asphalt mixtures thus

designed are typically placed with 7 percent air voids, or higher. This can result in lower than

desired asphalt pavement service lives due to durability loss as the asphalt prematurely ages.

Compacting asphalt pavements to 5 percent in-place air voids, without the possibility of further

densification from traffic would make them more durable thus extending asphalt pavement life.

Thus, producing asphalt mixtures with in-place air voids of 5 percent should yield better rutting

performance than compacting mixtures to in-place air voids of 7-8 percent, as is done currently.

Asphalt mixtures designed in the laboratory at 5 percent air voids can be compacted to

5 percent air voids in the field. A field test performed at a project near Fort Wayne and tests

performed at the National Center for Asphalt technology indicates this can be done without

additional compaction effort.

Changing the mix design through aggregate composition improves the durability of asphalt

payments, which translates to longer pavement life. The mix design asphalt content and the

field compaction effort will not change. The new design will not increase the cost of asphalt or

the construction costs to place and compact.

Analysis

The benefits of the project could be substantial. The possible increase in pavement life is

conservatively estimated at 2 to 3 years, a 12- 20 percent increase. This increase in pavement

life result in a significant reduction in life cycle pavement costs.

Calculations

Asphalt pavement life in Indiana is currently 15-20 years. Using a twenty-year life with an

estimated increase life of 12 percent (conservative) an extra 2.5 years is expected to be gained

from this new mix design. Using bid quantities, the area cost of asphalt pavement for a twenty-

year period was calculated. Using mainline pavement quantities, used in the SPR-2938 project

analysis, the following table indicates asphalt pavement lane miles for 2017 (actual) and 2018 –

2021 (estimated).3

29

2017 (actual) 2018 (est.) 2019 (est.) 2020 (est.) 2021 (est.)

237 lane

miles

80 lane miles 33 lane miles 28 lane miles 19 lane miles

From a typical cross-section for mainline pavement, the three asphalt courses have these area

weights.

• Surface – 165#/SY

• Intermediate – 275#/SY

• Base – 990#/SY for 25mm and 715#/SY (see 2938 calculations) for 19mm. Using the

lower of these two numbers will lower the sq. ft. cost of the pavement, therefore this

number was used.

For 1 SY of pavement the asphalt weight is 165+275+715 = 1155#, approximately ½ ton.

Asphalt cost (2017$, average) is estimated at $50/ton, so the in-place cost for 1 SY of mainline

pavement is $50/2(half ton) = 25$/SY.

Estimated new pavement value for each year is calculated.

• 2017 – 237 miles x 5280 ft./mile x 12 ft. wide pavement x 1 SY/9SF x $25/SY =

$41,712,000

• 2018 – 80 x 5280 x 12 x 1/9 x $25 = $14,080,000

• 2019 – 33 x 5280 x 12 x 1/9 x $25 = $5,808,000

• 2020 – 28 x 5280 x 12 x 1/9 x $25 = $4,928,000

• 2021 – 19 x 5280 x 12 x 1/9 x $25 = $3,344,000

Using an estimated 12 percent life increase, the extra value added for each year new pavement

is:

• 2017 - $41,712,000 x .12 = $5,005,440

• 2018 - $14,080,000 x .12 = $1,689,600

• 2019 - $5,808,000 x .12 = $ 696,960

• 2020 - $4,928,000 x .12 = $ 591,360

• 2021 - $3,344,000 x .12 = $ 401,280

These cost savings result from an additional pavement life value of 12 percent. The financial

analysis takes a present worth approach for a five-year period with expected capital cost of 3 percent.

The five-year period coincides with an INDOT proposed 5-year construction work plan which estimates

expected pavement quantities. Benefits are expected to accrue after the 5-year period, but are not

calculated, as pavement quantities are unknown.

30




Annual Benefit 5,005,440 1,689,600 696,960 591,360 401,280

Net Benefit-Cost -204,000 5,005,440 1,689,600 696,960 591,360 401,280

NPV $7,531,690.31


Summary



• 5 Year work program scheduling asphalt pavement estimates were used.

• Asphalt cost of $50/ton (2017$ cost)





References

1 Aschenbrener, T., R. Brown, N. Tran, P. Blankenship. Demonstration Project for Enhanced

Durability of Asphalt Pavements Through Increased In-Place Pavement Density. NCAT Report

17-05. National Center for Asphalt Technology at Auburn University,

Auburn, AL., 2017.

2 SPR- 3624 Final Report. Optimizing Laboratory Mix Design as it Relates to Field Compaction in

Order to Improve Hot-Mix Asphalt Durability. Available through Purdue e-Pubs.

3 Quantities provided by INDOT, John Weaver, INDOT Statewide Asset Management Engineer and

Andrew Pangallo, INDOT Field Engineer, [email protected].

31

SPR-3636: LRFD of Bridge Foundations Accounting for Pile Group-Soil Interaction

Introduction

Pile group foundations are used in most transportation structures. Traditionally, design of pile group

foundations has been performed in the United States using working stress design (WSD), which uses a

single value factor for safety to account for the uncertainties in pile design. A method that would enable

designs to reflect uncertainties in a more precise manner and be associated with a target probability of

failure would be advantageous with respect to WSD. Recognizing this, the Federal Highway

Administration (FHWA) mandated that load and resistance factor design (LRFD) be used for designing

the foundations of all bridge structures initiated after September 2007. In LRFD, load variability is

reflected in load factors applied by multiplication to the loads the foundations must carry, and

resistance variability is reflected in resistance factors applied by multiplication to the foundation

resistances. If load and resistance factors are determined using reliability analysis, it is possible to link

them to a probability of failure. In order to develop a comprehensive and reliable LRFD pile design

framework, it is necessary to have clear, detailed, and accurate understandings of the mechanism of

resistance development in pile groups. This project developed a number of analyses that provide

insights into pile group response that were not previously available. It then uses these analyses to

develop a first iteration of an LRFD design framework for pile groups. 1

Analysis

A total of six contracts; two in Crawfordsville District, three in Greenfield District and one in LaPorte

District were analyzed (2). Three projects have 14-inch pipe piles and the rest have steel H piles 12”x74’

or 14”x89’ driven to required nominal geotechnical resistances. This analysis compares two design

methods, the FHWA Driven pile analysis method and the INDOT-Purdue pile analysis method developed

through this JTRP project. Both these methods are compared with the results with pile dynamic load test

(PDA) at the beginning of restrike (BOR). Only one contract included Static Load Test (SLT) and a

comparison of the two design methods would not be conclusive.

Data from these contracts are shown in the below table. Based on this data, it appears that the Purdue

method developed in this project is more reliable.

Better design methods should predict resistances more accurately and precisely. It is difficult to

compare the impact of design methods in terms of cost, because pile length and resistance versus depth

is dependent on the specific soil profile and the distribution of axial and lateral loads. However, it is

possible to compare the impact of design methods on the excess capacity required to achieve a specific

level of reliability.

The below graph and table 2 shows a comparison of different pile capacity methods with the Purdue

method predicting higher capacities than the current used method and a closer correlation with PDA

results.

32

Calculations

Between 2008 to 2014, there have been 1,196,956 linear feet of piles installed on INDOT projects at a

total cost of $56,941,969 which corresponds to a unit cost of $47.57 per foot.2 Based on the test piles

driven on these six contracts which is 336 ft. and the load capacities between the current driven

analysis method and the Purdue method is 1845 kips to 2230 kips, or a 17% savings in pile driving costs.

Using the total pile cost between CY 2008-2014, the 17% savings is, $56,941,969 x .17 = $ 9,680,134.

This is over a 6-year period, or an annual savings $1,613,355.

33

The financial analysis used a present worth approach for a five-year period with expected capital cost


estimates expected bridge quantities. Estimated bridge quantities are estimated at the quantities

experienced during the 2008 to 2014 time period. Benefits are expected to accrue after the 5-year

period but are not calculated as bridge quantities may vary.



Annual Benefit 1,613,355 1,661,756 1,711,608 1,762,957 1,815,845

Net Benefit-Cost -416,000 1,613,355 1,661,756 1,711,608 1,762,957 1,815,845

NPV $7,199,825.62


Summary



• 5 Year work program scheduling 1,196,956 LF/6 years ~ 200,000 LF of piling annually.





References

1Han, F., Lim, J., Salgado, R., Prezzi, M., & Zaheer, M. (2015). Load and resistance factor design of

bridge foundations accounting for pile group–soil interaction (Joint Transportation Research

Program Publication No. FHWA/IN/JTRP-2015/24). West Lafayette, IN: Purdue University.

http://dx.doi.org/10.5703/1288284316009

2Provided by Mir A. Zaheer, Supervisor of the Geotechnical Design Services at INDOT

34

SPR-3705: Performance Assessment of Road Barriers in Indiana

Introduction

This research project investigated the performance of three types of median barriers: concrete walls, W-

beam guardrails, and high-tensioned cable barriers. A comparison of safety costs with respect to

installation costs shows the high-tensioned cable barrier option preferred.

Another outcome was to improve INDOT’s decision-making relative to all manner of barrier installation,

principally by optimizing economic benefits against cost of barrier hardware installation and recurring

maintenance.

Analysis

The basis of the cost benefit analysis is to project benefits of installing cable barriers that are planned in

the current five-year construction work plan. Possible future installations are expected, but are not

included in the analysis.

Calculations

Research cost was $150,000. The following analysis costs were provided by INDOT Division of Traffic

Engineering and Division of Maintenance.

Single-run high-tension cable barrier cost is approximately $120,000 per mile (1). Double-faced steel W-

beam barrier cost is approximately $170,000 per mile 1. Rigid concrete barrier cost is approximately

$1.5 million per mile (including necessary drainage inlets, extra offset of shoulder pavement width, etc.) 1. Each type has unique recurring maintenance costs.

A typical mile of high-speed (posted 70 mph) freeway with a conventional 60-foot-wide median and

elevated traffic volume, the design selection procedures developed in SPR-3705 reveal a per mile safety

cost benefit of $80,000 annually (2016$) produced by high-tension cable barrier relative to no barrier

separation, $30,000 annually in incremental benefit relative to double-faced W-beam, and $160,000

annually relative to rigid concrete barrier 1. Comparing the three options on a benefit/cost basis: cable -

80,000/120,000 = 0.66, W beam – 30,000/170,000 = 0.176, Concrete – 160,000/1,500,000 = 0.11. The

cable option has the highest benefit ratio and will be used in the financial analysis.

While actual mileage of median barrier consideration/construction on INDOT roads varies yearly, based

on past year records, 40 linear highway miles is a typical value and is used in the analysis. A five-year

new installation program will be calculated since it is scheduled in the work program. Barriers have an

expected service life of 20 years. Annual maintenance costs are $3,000 (2016$) per mile, which is

comparable to four other state’s cost 2.

The analysis will use the above basis for benefits, a service life of 20 years, and expected cost of capital

and inflation of 3%.

Below is the benefit cost analysis for the five-year work plan showing costs and benefits for a twenty-

year time period. For viewing purposes, the table is in two parts.

35

(a) Barrier cost = $120,000 * 40 (miles) adjusted for inflation

(b) Annual maintenance cost = $3,000 * (total installed cable barrier during the 5-year plan) adjusted for inflation

(c) Annual benefit = $80,000 * 40 (miles) adjusted for inflation

Summary

The benefit cost ratio for this project is 1,825 to 1. This number is based on the following:


• 5 Year work program scheduling 40 miles per year of cable median barrier installation.

• Cable barrier cost $120,000 (2016$) per mile.

• Estimated user cost savings is $80,000 (2016$) per mile per year.

36

• Estimated maintenance cost $3,000 (2016$) per mile.

• 20-year service life.





References

1 Provided by Brad Steckler, INDOT Director of Traffic Engineering, INDOT unit cost

2 Provided by Brad Steckler, verified by Todd Shields(INDOT Maintenance Field Support

Manager) and unit costs from 4 other state DOT agencies.

37

SPR-3830: Evaluation of Alternative Intersections and Interchanges

Introduction

This project evaluated the effectiveness of Diverging Diamond Interchanges (DDI) when compared to

Single Point Urban Interchanges (SPUI). Another product of the research was recommendations on

single phase signal timing design which has proven to improve traffic movement by reducing red time.

The final report provides recommendations on where to use DDI and has proven to be a reference

manual on DDI designs.

To provide a better understanding of the differences in the designs, an example of each is shown below.

SPUI

I-465 and Emerson Avenue in Indianapolis

In this design the bridge is widened to accommodate turning and through traffic lanes. The enlarged

bridge is an additional cost that is not included in the benefit cost analysis.

38

DDI

I69 and Dupont Road in Allen County

This design the bridge is smaller and traffic flows improved.

Analysis

Two DDI intersections were cited in the study. A DDI in Salt Lake City, Utah signals timing was studied

and with proper timing scheme traffic green time improved from 53% to 92%. The second was I69 and

DuPont Road in Allen County. At this interchange signal timing optimization was performed using

Bluetooth vehicle sensors. The optimization improved intersection travel times so that user costs were

estimated to save $564,000 annually. This number was calculated based on a methodology developed

by the Texas Transportation Institute (TTI) located at Texas A&M University. TTI derived a cost of

congestion equation which is determined by computing the average delay for a section and multiplying

it by the expected traffic volume and the value of time. Added to the congestion cost is the CO2

emission cost. Combining the congestion and emission costs is the user cost. AADT values for these

calculations is provided by INDOT.

This study has determined DDI to be more cost effective than SPUI interchanges with certain site and

traffic conditions. Currently INDOT has two more DDI interchanges at exit 210 on I-69 and exit 93 on I-

65. Plans are to build two annually in the next four years. Using annual cost savings for each

interchange and with 3 currently in place and plans to add 2 each year for the next 4 years is what the

cost savings calculations are based on.

Calculations

2017 annual cost savings with the current 3 DDI interchanges = $564,000 x 3 = $1,692,000

2 additional DDI interchanges added each year for years 2018-2021. Cost savings for each year by using

the DDI option over the SPUI configuration is shown below.

39

2018 – $564,000 x (3 (previous)+2) = $2,820,000

2019 - $564,000 x (5 (previous) + 2) = $3,948,000

2020 - $564,000 x (7 (previous) +2) = $5,076,000

2021 - $564,000 x (9 (previous) +2) = $6,204,000



Annual Benefit 1,692,000 2,820,000 3,948,000 5,076,000 6,204,000

Net Benefit-Cost -235,000 1,692,000 2,820,000 3,948,000 5,076,000 6,204,000

NPV $17,029,517.80


Summary

The benefit cost ratio for this project is 72. This number is based on the following:


• 3% cost of capital.




References

1. Day, C. M., Stevens, A., Sturdevant, J. R., & Bullock, D. M. (2015). Evaluation of alternative

intersections and interchanges:

Volume II—Diverging diamond interchange signal timing (Joint Transportation Research

Program Publication No.

FHWA/IN/JTRP-2015/27). West Lafayette, IN: Purdue University.

http://dx.doi.org/10.5703/1288284316012

2. Remias, Stephen, M., T.M. Brennan, C.M. Day, H.T. Summers, D.K. Horton, E.D. Cox and D.M.

Bullock, “Spatially Referenced Probe Data Performance Measures for Infrastructure Investment

Decision Makers,” Submitted to Transportation Research Board, , Paper No. 14-1062. In Press.

August 1, 2013.

3. Phone Interview, Jim Sturdevant, 10/20/17 and 12/6/17.

indot research program benefit cost analysis – … 17 roi final report 12...5 * based on indot 5...

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