Review of the Virginia Department of Transportation’s Truck Weight Data Plan for the Mechanistic-Empirical Pavement Design Guide

About the report:

In 2003, staff of the Virginia Transportation Research Council (now the Virginia Center for Transportation Innovation and Research) and the Virginia Department of Transportation (VDOT) developed a plan to collect traffic and truck-axle weight data to support the Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures, known as the Mechanistic-Empirical Pavement Design Guide (MEPDG).  The purpose of this study was to review VDOT’s traffic data plan for the MEPDG and revise it as needed.  The review included an assessment of the data obtained from the VDOT and Virginia Department of Motor Vehicles weigh-in-motion  (WIM) sites and the appropriateness of the truck weight groups in VDOT’s traffic data plan.  Information on truck travel patterns and characteristics was compiled. 

 There is very little literature that provides specific information on the structure of a traffic data plan for the MEPDG.  Guidance provided by the Federal Highway Administration allows for much flexibility in the development of such a plan.  Most states are working to develop the plan, and such plans that are already in place vary considerably.  The Corridors of Statewide Significance in Virginia’s statewide long-range multimodal transportation plan represent the routes where truck traffic is most prominent and therefore represent routes on which the VDOT plan should focus. 
 
 The study recommends that VDOT continue with its current truck weight data plan for the MEPDG.  With this plan, VDOT is positioned to implement the MEPDG from a truck data perspective.  The WIM data comprise an important input to the MEPDG process that is expected to provide VDOT with more accurate pavement designs based on actual traffic loadings in Virginia.  Further, staff of VDOT’s MEPDG Traffic Data Team and staff of the VDOT Traffic Engineering Division’s Traffic Monitoring Program should work together to develop a strategic plan for the continuing incremental expansion of the WIM program.  The plan should include consideration of the resources needed not only to add sites but also to administer an expanded WIM program.  VDOT’s Chief Engineer and Chief of System Operations should encourage the addition of WIM sites when major projects are planned in locations that are part of the strategic plan for WIM.  Site characteristics required for acceptable WIM sensor performance should be specified by VDOT’s MEPDG Traffic Data Team.  Implementation of the recommendations provided in this study will assist VDOT in using the MEPDG to advance pavement design and improve its cost-effectiveness.  The likelihood of implementation is high. 

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