WRI researchers have derived expected bottleneck evacuation loads for the Santa Barbara region. Below is a link to an interactive site that displays the total population divided by number of limiting exit lanes for zones / clusters in the region.

Evacuation impact interactive map

Technical details and a description of the methodology are forthcoming. The basic idea is identifying an area that is restricted in terms of evacuation capability. As an example, the interactive map highlights portions of Isla Vista / UCSB, an area that has a population of 24,754. The indicated area has three single lane exits: Storke Rd (north of Sierra Madre Ct), Los Carneros Rd (north of Mesa Rd) and 217 (exiting UCSB). This gives an evacuation load of 8,251 people per lane (24,754 / 3), by far the highest observed in the Santa Barbara region.

Background information can found in the following work seeking to identify critical evacuation clusters:

• Cova and Church (1997), Modelling community evacuation vulnerability using GIS. International Journal of Geographical Information Science, 11(8), 763-784
• Church, R. L., & Cova, T. J. (2000). Mapping evacuation risk on transportation networks using a spatial optimization model. Transportation Research Part C: Emerging Technologies, 8(1-6), 321-336.

Note that these are preliminary findings based on interpolated 2020 US Census block data. Further, we have observed irregularities in the associated transportation network data, so are actively working to correct them and report updated figures.

For additional information, contact Alan Murray.