Modeling the impacts of speed limits on uncertain road networks

In this paper, we examine the network-wide impacts of speed limits on network uncertainty. A multi-dimensional modeling approach is proposed to investigate the impacts of speed limits on link travel time uncertainty profile, travelers' risk-averse route choice decisions, and network flow reallocation under uncertainty. Methodologically, a truncated travel time probability distribution is proposed and its moments are derived to characterize the impact of speed limit on link travel time uncertainty profile. The mean-excess travel time is then adopted as a risk measure to account for travelers' risk-averse route choice adjustment and network flow reallocation induced by speed limits. We find that a speed limit scheme has different impacts on various dimensions of travel time uncertainty. The shift in travel time uncertainty profile of the directly affected links adjusts the traveler's risk-averse route choice decisions, the travel time uncertainty profile of the indirectly affected links, and consequently the network flow reallocation.