Work Zone Impacts

Module 5

What is a WZ Impact Assessment?

WZ Impact Assessment is the process of understanding the safety and mobility impacts of a road construction or maintenance project

Basic Concept

Determine impacts of project? Acceptable? If yes, no problemUnacceptable? (Significant project)

Can strategy be found to mitigate impacts to acceptable level?

Yes – develop TMP No – determine best strategy Advise stakeholders of possible problems

WZ Impacts Considerations Maximizing Safety

Road UsersWorkers

Maximizing mobility and accessibilityRoad user costsEmergency servicesBusinesses

ConstructabilityBuilding projects effectively and efficiently

Benefits of Assessing Impacts Identify and understand all impacts of the project Identify “significant projects” and determine

suitable TMP Aid in identifying and evaluating alternative

strategies Monitor and manage WZ impacts during

construction

Mobility Impacts Mobility Issues

Delay Reduced quality of life issues Significant Projects – agency definition Reduced Speeds Queues and complete stoppages

Freight Interference Travel time reliability – biggest concern Delayed deliveries Unanticipated costs

Emergency response

Causes of Recurring Congestion

Non-recurring Congestion

Safety Impacts Road user exposure to hazards

Will staging create safety hazards greater than existing?

Worker exposure to trafficStaging allow for positive protection?

Geometrics during phases Availability of law enforcement Speed reduction necessary/considered?

Business Impacts Access

Temporary entrances Signing Pavement

Advance notification of phase changes Keep owners informed

Work Schedules Christmas shopping season Weekends

Residential Access Impacts

Keep residents informed as project begins and progresses Neighborhood

association meetings, newsletters, mailings, etc.

Maintain access if possible

Incident Response Impacts

Ensure access to all areas for emergency vehiclesHospitals nearby?Trauma centers?

Plan to provide access within work site Identify alternate routesPre-sign for use during incidents?

Transit Impacts Transit route through project?

Bus stopsAlternate routes available Include in PR information

Pedestrian Impacts

MUTCD Part 6D: If project affects the

movement of pedestrians, adequate pedestrian access and walkways shall be provided.

Impact Assessment Proactive versus reactive Use early in the TMP Development

process to identify and estimate the magnitude of the impacts

Assess impacts on regional basis Use assessment to help evaluate various

strategies for mitigating impacts Possibly use assessments to justify TCP

revisions after award of project

Goal

A good impact assessment process should keep agency from being surprised after project is underway – when it is too late to consider strategies to reduce impacts.

Mobility Impact Assessment Tools Historical knowledge – “Lane closures do not cause

backups on this segment of road…”

Various levels of tools for more detailed analysis Sketch Planning Tools Travel Demand Models Traffic Signal Optimization Tools Macroscopic Simulation Models Mesoscopic Simulation Models Microscopic Simulation Models

WZ Analysis Tool Model Spectrum

Transportation Model Approachesmacro

meso

micro

MacroscopicDelay Estimation Tools

Basic Concept Special-purpose delay

estimators for work zones

Examples: QuickZone, DELAYE, QUEWZ-98

Strengths Relatively easy-to-use,

rapid analysis Weaknesses

Limited capability beyond modeling simple “pipeline” analyses

High-level analysis

macro

MacroscopicRegional Planning Models

Basic Concept Steady-state liquid flow Examples: TRANPLAN,

EMME/2, TransCAD, others

Strengths Can handle very large

networks (metro areas) Weaknesses

Not time sensitive Complex models,

relatively expensive to build and maintain

macro

Mesoscopic

Basic Concept Particle Flow Vehicles are located on roadways but not specific lanes

Examples: DYNASMART-P, DYNAMEQ Strengths

Can model sub-regional areas in major metropolitan areas Weaknesses

Not detailed enough for some operational strategies (e.g., complex signal control) Model complexity is high, data and calibration resources are significant

Microscopic

CORSIM, VISSIM, and othersModel individual vehicle movementsRequires extensive resources to establish and

calibrateUsually reserved for large and complex

projects unless existing model can be utilized

Work Zone Analysis Primer

Aid in selection of the correct tool to use in the analysis

Provide guidance to reviewer to ensure appropriate tool was selected for project

Work Zone Modeling and Simulation Volume IX

Case studies Aid for analysts

How Should Results of Assessment Be Utilized? Formulate policies Identify strategies that will minimize

impacts Identify critical issues to address in

development of TMPAlternate route availabilityEffects on businesses and residents

Results Used to Formulate Policy

Ohio DOT MOT/PLC Policy

TMP Development ProcessIdentify Early in Process

Analyzing Strategies

MNDOT Specific – Fig. 1

Impacts Assessment at Project Level

Consider WZ impacts in the assessments that are performed during alternatives evaluations.

Allocate sufficient fundsAddress impacts of multiple projects

Work Zone Impacts Assessment During Preliminary Engineering1. Compile project /WZ Scope Information for

Alternatives2. Assess WZ Impacts of Alternatives at a

Screening Level3. Analyze Potential Impacts (optional)4. Identify WZ Management Strategies5. Perform Plan/Program Level WZ Impacts

Assessment6. Compile Planning-Level Work Zone Strategy

Compile project /WZ Scope Information for the Alternatives

The major categories of information that may be needed include the following: Project Scope Roadway/Traffic Characteristics Other Influencing Factors

Identify WZ Management Strategies

Issues To Be Addressed In Identifying WZ Management Strategies: TTC Strategies TO and PI Strategies. Coordination Strategies with Other

Projects. Costs for the Management Strategies

How to Incorporate WZ Impacts Assessments During Design Compile Preliminary Engineering Materials Reassess WZ Impacts Develop/Recommend Final Construction Staging

and TMP Advertise and Award Contract

Work Zone Impacts Assessment During Construction Assess the impact of any proposed changes prior to the

start of work Implement the TMP. Actively monitor and manage work zone impacts during

construction. Revise the TMP and implement appropriate revisions, if

necessary. Document any findings or lessons for use in

performance assessments.

Example ChecklistDDOT

Example ChecklistDDOT Guide

Example ChecklistDDOT Guide

Example ChecklistDDOT Guide

Michigan TMP Template

Michigan TMP Template

http://www.ops.fhwa.dot.gov/wz/resources/final_rule/mdot_tmp_template/mdot_tmp_template.pdf

Review and Discussion

When should the Impacts Assessment take place in the TMP process?

Does your state have a procedure in place to assure impacts are factored in to the project planning and design?