Background

This case study presents how the Virginia Department of Transportation (VDOT) estimates traffic volumes on secondary local roadways using a trip generation method instead of taking short-duration counts in the field. The use of trip generation estimates was an outcome of a review process that aimed to reduce data collection costs and achieve manpower savings by establishing a local secondary count program. As part of this program, VDOT provided guidelines to its staff on how to identify eligible traffic links and generate traffic volume estimates using the trip generation method. According to this program, region and district staff are responsible for reviewing candidate segments using aerial photos, determining potential development and roadway connectivity, evaluating roadway eligibility criteria, documenting the trip generation process used, developing estimates, and submitting the estimates to the Central Office-Traffic Engineering Division. After implementing the method, VDOT realized several benefits, most of which are associated with time and cost savings. Because of the positive experience and feedback received with this effort, VDOT will continue to promote and improve the use of the trip generation method.

Read the Case Study Virginia Department of Transportation: Innovative Procedures in Traffic Volume Estimation for more detailed information.