Optimizing scheduling of long-term highway work zone projects

The impacts of work zone activities can be summarized into the following types: safety impact (on both motorists and workers), mobility impact, economic considerations, environmental concerns, user cost as well as contractor's maintenance cost. Various interest subjects may focus on different aspects of the six areas identified above. In this study, the impacts of scheduling long-term work zone activities are analyzed from the perspective of traffic agencies and jurisdictions. A bi-level genetic algorithm (GA)-based optimization model is formulated to determine the optimal starting date of each work zone project. The upper-level subprogram minimizes the total travel time over the entire planning horizon, while the lower-level subprogram is a user equilibrium (UE) problem where all users try to find the route that minimizes their own travel time. The demand, and the number of work zones as well as their durations are assumed to be fixed and given a priori. The proposed GA model is applied to the Sioux Falls network, which has 76 links and 24 origin-destination (O-D) pairs. The results of the numerical example indicate that the proposed model can effectively identify the near-optimal solution of the long-term work zone scheduling problem.