Available at: http://digitalcommons.calpoly.edu/theses/671
Date of Award
MS in Civil and Environmental Engineering
Civil and Environmental Engineering
In recent years transportation professionals have shown increasing interest in evacuation planning. With the advances in computing technologies it is possible to simulate urban transportation networks with great detail. These details from the traffic simulation model can be used for devising strategies for evacuation and emergency response in case of a disaster.
This thesis describes the modeling, calibration, and validation of the VISSIM traffic simulation model coded for downtown San Jose. The network is then used to test various evacuation scenarios to assess evacuation strategies that would be effective in case of a human-caused disaster.
The network modeled in the simulation software VISSIM required a large amount of data regarding network geometry, signal timings, signal coordination schemes, and turning movement volumes. Turning movement counts at intersections were used to validate the network with an empirical formula to assess the differences between observed and simulated counts. For freeways the simulation model was validated using the actual travel time information. Once the base network was validated, various scenarios were tested to estimate evacuation and emergency response vehicle arrival times.
It was found that in the event of coordinated terrorist attacks (specified in the disaster scenario) simultaneously occurring at four locations in the downtown San Jose area, severe bottlenecks would result due to evacuee traffic. To alleviate the congestion, contraflow lanes should be used on Montgomery Street (which becomes Bird Avenue) to help reduce congestion. While contraflow lanes helped the situation, traffic incidents potentially resulting from all the chaos could complicate evacuations.
The investigators found that reducing the number of vehicles on the road through public transit ridership would be the optimal approach, while leaving area roads uncongested for the emergency response personnel. In the scenario where 30% of the evacuees used transit at Diridon Transit Center, the travel times for the remaining evacuees, as well as the first responders, were minimized. None the less, the other scenarios were also critical to this study, since they provided a response strategy in case the transit station is affected by the attacks.