Evaluating the Impacts of Variable Message Signs on Airport Curbside Performance Using Microsimulation

Inefficient curb space allocation increases congestion and emissions at airports. Variable message signs (VMS) can alleviate this issue, guiding vehicles from congested to underutilized curbs. However, VMS effectiveness hinges on the right activation and deactivation timing. Using a microsimulation model of the Seattle-Tacoma International Airport, we analyzed the impacts of implementing VMS and determined the best time to turn the sign on and off. We simulated sixteen VMS management scenarios and compared the results against those of a baseline where there was no VMS. We found that strategic and timely management of the VMS is crucial to achieving improvements in congestion and curb performance. Specifically, activating VMS before congestion started on the sending link and deactivating it before congestion began on the receiving link substantially improved curb productivity and accessibility, vehicle delay, and CO₂emissions. On the other hand, if not managed correctly, VMS may lead to little to no improvements, or even negative impacts on traffic conditions and curb performance. For instance, late activation or deactivation can worsen curb accessibility and vehicle delay. Our framework provides valuable insights into how airports could successfully manage VMS technologies.