摘要: |
This study tested a dynamic traffic assignment (DTA) model as a tool for pre-planning strategies for managing major freeway incidents. Incidents of varying scale and duration were modeled in the northern Chicago highway network, and the impacts of incidents and response actions were measured in terms of both lane-mile-hours of highway links at level of service (LOS) F and in the spread of congestion to alternate routes around the incident. It was found that the best response action to a given incident scenario is not necessarily intuitive, and implementing the wrong response can worsen congestion on both the directly impacted freeway and its surrounding highway network. The simulation model showed that a full closure of the freeway causes congestion to spread to parallel alternate routes around the simulated incident. An event at this scale constitutes a major disruption that may warrant handing off traffic control authority from first responders to a corridor or regional traffic management center (TMC). Major arterials accessible from the incident impacted freeway sometimes needed increased capacity to provide access to less congested parallel alternate routes during incidents. The simulation model showed that congestion increases with delayed response, underscoring the benefits of pre-planning to speed the implementation of effective incident response actions. Regression analysis using data generated by the simulation demonstrates that both incident scale and duration are statistically significant predictors of lane-mile-hours of congestion in the zone near the incident and on the expressway. |