Wildfire Evacuation Scenario in Colorado

Abstract

In late 2010, the City of Colorado Springs and the Pikes Peak Area Council of Governments in Colorado completed a cooperative wildfire evacuation planning process. The process was supported by the simulation of wildfire evacuation scenarios with an adaptation of the Council of Governments’ four-step travel model. The adapted model was used to assess times to evacuate, identify choke points, and develop traffic control plans for identified at-risk neighborhoods. Evacuation simulations used a worst-case scenario in which the wildfire event took place during the p.m. peak traffic hour, and affected households were included in both background commuter traffic and neighborhood evacuation traffic. Link-based hourly volume-to-capacity ratios were used as a metric to estimate times to evacuate and to identify egress bottlenecks. Route closures, route restrictions, no-entry restrictions, and contraflow operations were evaluated as measures for inclusion in neighborhood-level traffic control plans. On Tuesday, June 26, 2012, the simulated worst case became reality. More than 34,000 persons were evacuated during the event, including 26,000 during the 6-h period between 15:30 and 21:30. Before the wildfire was fully contained, 18,247 acres had burned, 347 homes and other structures had been destroyed, and two people had died. That the no-notice, mandatory evacuation was as successful as it was can be attributed to extensive advance planning, the accuracy of modeled evacuation simulations, and the effectiveness of the final traffic control plans. This study examined how the model results were borne out by actual experience. Recommendations to improve no-notice evacuation planning from the perspective of lessons learned are presented.