Construction Traffic Analysis: To be or Not to be

A Case Study for NC-107 Widening, Sylva NC

Presented by

Taruna Tayal,

Donald A. Bryson, PE November 16, 2016

Project Background and Concerns

Major north/south

transportation corridor in

Jackson County

Northern Loop around Sylva

and Dillsboro

27,000-39,000 AADT in 2035

Congestion

Safety

Prioritize improvements

Implement traffic calming

devises

Minimize impacts to

surrounding businesses

NC-107 Corridor

Mostly commercial development

Few educational facilities

Approximately 95 driveways intersect this corridor

Sparse residential and commercial development

Fourteen signalized intersections along US 23 Business and NC 107

Modeling and Analysis

Design – Synchronized

Street

TransModeler Micro-

Simulation analysis

Scenarios studied

– 2015: Build and No-Build

– 2025: No-Build and

Construction

– 2035: Build and No-Build

Attributes Compared

– Level of Service

– Travel Time

– Delay (sec/veh)

– Queues

Design and Analysis

Courtesy: NC 107 Corridor Study Report

Jackson County Regional Model for

Growth and Base network

Network disaggregated in

TransModeler for finer geography

ODME in TransModeler for 2013 trip

table

Fratar for FY trip table

Modeling

Design and Analysis

2025 Under Construction

2035 Build

Findings

Travel Time Savings and LOSSkyland Drive to Fairview Road

Performance

MeasureTime of Day Direction

Construction Year (2025) Future Year (2035)

No Build

Under

Construction No Build Build

Travel Time

(minutes

(AM Peak

Hour)

Northbound 6.3 6.6 13.3 5.5

Southbound 12.6 9.4 18.7 14.4

(PM Peak

Hour)

Northbound 13.4 22.3 28.3 7.9

Southbound 12.5 12.7 19.2 14.3

Average

Speed (Miles

per hour)

(AM Peak

Hour)

Northbound 28.8 27.5 10.1 23.6

Southbound 14.4 19.3 7.0 9.2

(PM Peak

Hour)

Northbound 13.5 8.1 5.1 16.8

Southbound 14.5 14.3 6.9 9.6

LOS

(AM Peak

Hour)

Northbound B B F C

Southbound E D F F

(PM Peak

Hour)

Northbound E F F D

Southbound E E F F

Delay Savings (Seconds/Vehicle)

-500.0

-400.0

-300.0

-200.0

-100.0

0.0

100.0

200.0

300.0

US 23 Business/ Skyland Drive

NC 107 /Chipper Curve

Road

NC 107 / US 23Business

NC 107 /Cherry Street

NC 107 / CopeCreek Road

NC 107 / Wal-Mart Entrance

NC 107 / JonesStreet

NC 107 /Lowes

Entrance

NC 107 / NC116

NC 107/Fairview Road

Construction Year (2025) AM Peak Hour Construction Year (2025) PM Peak Hour

Design Year (2035) AM Peak Hour Design Year (2035) PM Peak Hour

AM Peak Hour Southbound Queue Length(Feet)

0

200

400

600

800

1000

1200

NC 107 / US 23Business (Asheville

Highway)

NC 107 / CherryStreet

NC 107 / CopeCreek Road /

Walter Ashe Road

NC 107 / Wal-MartEntrance

NC 107 / JonesStreet / Brysons

Farm Road

NC 107 / LowesEntrance

NC 107 / NC 116(Webster Road)

NC 107/ FairviewRoad

Constrution Year (2025) No-Build Constrution Year (2025) Build Design Year (2035) No-Build Design Year (2035) Build

PM Peak Hour Northbound Queue Length(Feet)

0

200

400

600

800

1000

1200

1400

1600

NC 107 / US 23Business (Asheville

Highway)

NC 107 / CherryStreet

NC 107 / CopeCreek Road /

Walter Ashe Road

NC 107 / Wal-MartEntrance

NC 107 / JonesStreet / Brysons

Farm Road

NC 107 / LowesEntrance

NC 107 / NC 116(Webster Road)

NC 107/ FairviewRoad

Constrution Year (2025) No-Build Constrution Year (2025) Build

Design Year (2035) No-Build Design Year (2035) Build

Conclusion and

Lessons Learned

Work zone implementation strategies such as lane closures and

time restrictions,

Phase construction

– Construction of U-turn bulb-outs

– Southbound outside widening

– Northbound outside widening

– Median widening

Left turns may be considered from NC 107 to northbound US 23

Business (Asheville Highway)

Add roundabout at the intersection of Caldwell Street and Cherry

Street

Recommendations

Pros and Cons

Better Construction

Revise interim and final design

Help the businesses understand

the impacts

Costly Analysis

Only Peak Hour impacts

No Construction safety

Performance Measures

& Construction Impacts

Travel time savings =

critical performance measure

Should construction

impacts be considered?

Excellent case study– No feasible alternate routes

– No practical transit / TDM options

– Simple but realistic assumptions

Considers only travel delay benefits

Reducing Travel Delay

Chart

CONSTRUCTION

OPEN

Chart

Cost Benefit AnalysisCONSTRUCTION

OPEN

Chart

Cis

0%

2%

4%

8%

($5,000)

($2,500)

$0

$2,500

$5,000

$7,500

$10,000

$12,500

$15,000

$17,500

2 0 2 4 2 0 2 5 2 0 2 6 2 0 2 7 2 0 2 8 2 0 2 9 2 0 3 0 2 0 3 1 2 0 3 2 2 0 3 3 2 0 3 4 2 0 3 5

AN

NU

AL

SAV

ING

S IN

20

14

DO

LLA

RS

(10

00

'S)

EFFECT OF DISCOUNT RATE ON CUMULATIVE DELAY SAVINGSANNUAL TRAVEL T IME SAVINGS IN $1000S

0%

2%

4%

8%

CONSTRUCTION

OPEN

http://tcsidewalks.blogspot.com/2013/03/what-does-peak-vmt-mean-for-twin-cities.html

US VMT (12-Month Moving Total)

1990 2000 2010 20202015 202520051995

Other construction impacts…CONSTRUCTION

OPEN

Fuel consumption?

Economic impacts?

Air quality?

Safety?

Construction impacts can be significant– New alignment vs widen existing

– Evaluate:

• Operational improvements

• Demand management

• Alternate modes

– Is rigorous construction planning justified?

Beware of “end-state” planning– Interim matters

– Immediate vs long-range impacts

Benefit/Cost: Simple Complicated

What about uncertainty?

Things to ponder:

23 offices throughout the east coast

www.vhb.com

Taruna Tayal| ttayal@vhb.com | 919.741.5525

Donald A. Bryson | dbryson@vhb.com | 919.334.5615

Questions / Comments