Identification and evaluation of flood-avoidance routes in Tucson, Arizona

Abstract

Campaigns such as “Turn Around, Don't Drown®” encourage motorists to avoid driving into flooded roadways, but thousands of flood-vehicle incidents occur each year. Motorists may not have a feasible alternate route, or they may not be aware of one. Furthermore, few studies within hazards research consider how vulnerability changes as an individual moves through space. A survey of Tucson, Arizona residents included a mapping activity to determine whether their typical routes intersect flood areas, and whether alternate routes exist that avoid flood areas without adding excessive travel time. Of the 452 routes provided, 185 intersect with areas known to flood during routine rain events, affecting 80% of participants. ANOVA revealed no statistically significant differences in exposure rate among groups based on demographic characteristics. Network analyst was used to generate alternate routes that avoid the flood areas and to calculate how much additional time and mileage would be required. Most of the alternate routes added less than one mile to the trip, which is within participants' stated detour tolerance. These findings highlight the potential utility of a decision-support tool to help motorists choose safer, flood-avoiding routes during storms.