Developing a Testbed for Evaluating the Impacts of Truck Performances on Surrounding Traffic

The high percentage of trucks combined with the mountainous terrain along the I-81 corridor in the state of Virginia has resulted in significant capacity reduction and delay increases. Different alternatives are being considered in order to alleviate the capacity impacts of trucks along I-81. These alternatives may include adding lanes along grade sections, reducing grade through a re-alignment of the interstate, considering alternate modes for transporting goods, or even reducing the number of trucks on the interstate during peak periods.

The evaluation of these alternative measures requires a sophisticated evaluation tool that not only captures the dynamics of trucks as they travel along grades, but also accurately captures the formation of shockwaves behind these trucks. This project demonstrates the effectiveness of the INTEGRATION model as such an evaluation tool through the modeling of a 30-mile segment of I-81 between Roanoke and Christiansburg.

Initial simulation results indicate that trucks experience delays that exceed light vehicle delays by as much as 18%. The results obtained showed that the 100 lb/hp truck was the most economical. The 100 lb/hp truck gave the best average travel time followed by the 200 lb/hp, combined, and 300 lb/hp trucks, which were represented by an increase that ranged from 16% to 63% for the AM peak traffic, and 26% to 120% for the PM peak. There were a total of 8085 vehicles discharged during the AM peak as opposed to the 10060 vehicles that were discharged during the PM peak, a 24% increase over the AM peak.