Vermont Agency of Transportation (VTrans) Statewide Travel Model Peer Review Report

Peer Review Session 4: Recommendations from Peer Review Panel

Date :

July 31, 2013

Current Model Strengths

Inclusion of travel data/surveys (NHTS, ACS, Vermont Dept. ofLabor, Traffic Counts)
Reliable state-estimated demographic forecasts
Inclusion of HBW school trips with HBW trips to minimize use of special generators
Application of vehicle occupancy rates for privately owned vehicles only and not for transit vehicles
Use of TAZs/links from regional travel models to increase resolution
Consideration of speed zone layers if time-of-day model is pursued

General Recommendations

Expand the external model area by including a halo over the state line
Expand roadway network to include interstates, major arterials, and collectors with accurate speeds, lengths, and classifications
Reassess centroid connectors
Consider seasonal trip tables
Consider future year beyond 2030
Establish one freight model component based on either commodity flows or truck/rail vehicles
Develop in-house expertise in application of the model

Consistent Themes in Response to Seven Questions

Focus on a single model platform
Strengthen agency understanding of model sensitivity and appropriate uses for statewide model application
Minimize dependence on the one statewide model by developing consistent/compatible tools to meet agency needs
Identify project types and metrics desired for project prioritization before redesign of model features

(1) Response to FHWA Identified Issues

Address fundamental model development considerations from FHWA
Develop Users' Guide and Technical Reference
Define short/medium/long term priorities based on current model - For example:
- Short-Term: Create one comprehensive statewide model package,

Check consistency between sub models, Assess appropriateness of model to meet agency needs

Mid-Term: Identify second phase of model enhancement (to occur while the current model is in use) based on agency priorities
Long-Term: Develop "wish list" of features that are lacking from the Short- and Mid-Term enhancements

(2) Resiliency Planning

Consider dynamic traffic assignment to assess traffic patterns in emergency response
Identify metrics for alternatives comparison to guide model development
Develop at-risk location inventory in network via link attributes
Automate the incorporation of at-risk location data into the network
Recognize that emergency contingency planning is associated with links damaged by an emergency event not general facility design

(3) Evaluation of Energy/Emission Goals

Include a mode choice model component
Identify sensitivities in energy/emission performance measures
Recognize difficulty in addressing performance measures given scale/resolution of statewide model - more appropriate for regional model
Consider a separate aggregate model to apply data from the statewide model and the MPO model to evaluate energy/emissions information
Consider scenario testing in the long-term

(4) System Preservation and Disinvestment

Identify performance measures desired for project prioritization before adjusting model
Review Oregon's HERS-ST (applies statewide model growth rates to evaluate needs/options) for transportation investment optimization
Consider evaluating volumes and road wear for project prioritization
Coordinate with pavement program staff to determine need for this type of effort

(5) Performance Measurement & Asset Management

Identify/prioritize model design features for each performance metric desired based on agency needs
Develop post processing methodology to determine economic impact/GDP value of individual links
Apply additional economic assessment software (STEAM, T-PICS, TREDIS, REMI, Transight) to model output
Consider use of a separate project-specific benefit/cost model

(6) Fair-Share Methodology

Develop VMT estimates for new development by land use type and trip purpose to determine change over time/assess impact fees
Recognize that statewide model resolution is not adequate for the post processing methodology to determine long-range growth rates for background traffic
Consider micro-simulation model which applies future volumes/growth rates from the regional model
Look into off-model techniques for development impact assessments (ITE Trip Generation Manual) for use as a separate/compatible tool

(7) Corridor Prioritization: Transit, Biking, & Waking

Recognize that statewide model may not be appropriate resolution for evaluating non-motorized transportation improvements
Develop separate/compatible tool for non-motorized transportation
Consider micro-simulation models for local area analysis
Consider survey efforts to understand current travel by mode
Consider tiered approach to activity-based model development for non- motorized travel as a long-term priority