In-Depth Analysis of Vehicle Following Gaps in Highway Work Zones: Direct and Interdependent Impact of Leading Vehicle

This paper analyzes the impacts of various vehicle following patterns on the vehicle following distance/gap in highway work zones. It studies the direct impact of leading vehicle on the vehicle following gap in 2-vehicle platoons and interdependent impact of the leading vehicle on the vehicle following gap between the 2nd and 3rd vehicles in a 3-vehicle platoon. The collected dataset is comprised of more than 15000 observations. Four 2-vehicle patterns and eight 3-vehicle patterns are grouped and average gaps from different patterns are compared to study the direct and interdependent impact of leading vehicle on the following distance. The ‘unpaired two-sample t-test’ was conducted to determine the significant differences at a 5% significant level. Sixteen hypotheses tests were performed to find the direct impact, and 32 hypotheses tests were used to identify the interdependent impact of leading vehicle on vehicle following gap between the 2nd and 3rd vehicles in 3-vehicle platoons. It is found that truck drivers maintain a significantly longer gap than car drivers when led by the same type of vehicle in both short-term and long-term work zones. In either long-term or short-term work zones if middle vehicle is truck in 3-vehicle platoons, then there is no significant impact of the leading vehicle type on the vehicle following gap between the 2nd and 3rd vehicles. The work zone type appears to have no influence over the vehicle following gap between the 2nd and 3rd vehicles, when the 3rd vehicle is truck.