Incident Management Simulation on a Freeway Corridor in Honolulu
Made Public Date

Incident Management Simulation on a Freeway Corridor in Honolulu

Summary Information

This study simulated incident duration and motorist response to real-time traffic information on the Moanalua and H-1 freeway corridor in Honolulu, Hawaii. Capacity changes were measured on each freeway using statistical estimates of driver uncertainty, and simulations of driver behavior using real-time traffic information in the form of dynamic message signs (DMS) and highway advisory radio (HAR).

The following three scenarios were analyzed using the INTEGRATION simulation model:
  • Existing or Base Case Scenario.
  • Incident with No Incident Management (IM) Scenario.
  • Incident with IM Scenario.

Baseline incident duration data was extrapolated from previous studies of incident duration in the U.S. between 1970 and 1995. Based on this information a simulation model was designed that blocked one lane of the Moanalua Freeway for 40 minutes and then assumed the incident would be moved to the shoulder for 20 minutes. In addition, it was assumed that 15 percent of motorists would reroute to avoid major incidents if No IM program was in place, and 40 percent would reroute if IM programs were available.

The simulation model also assumed the following parameters:
  • Incident response times would be moderate since mobile phone signals were readily available and immediate congestion would illicit prompt phone reports.
  • Trip departure time changes due to pre-trip traveler information were not considered.
  • Only eastbound freeway traffic was modeled.
  • The model simulated traffic activity from 10:00 AM to 11:30 AM.
  • Secondary roadways were ignored, however, intersections with the arterials were included.
  • The simulation did not consider trips between origin-destination (O-D) nodes that did not completely traverse the network.



Total Network Travel Time (Vehicle Hours)

Travel Time in Excess of Baseline (Vehicle Hours)

Existing Conditions


No-IM and 60 min. Incident (15% reroute)



IM with 60 min. Incident (40% reroute)



These results show significant travel time savings with an IM program in place.

Real time information to motorists caused diversions from the Moanalua Freeway to the H-1 Freeway and reduced delay by 40 percent compared to the No-IM scenario; however, the author noted that diversions were only feasible as long as sufficient capacity existed along alternate routes since ramps have often been a limiting factor, and not the main-line capacity.
Goal Areas