One of the many lessons learned in the wake of the Camp Fire last year was the vital role of evacuation routes. Traffic stalled on clogged roads as residents tried desperately to get out.
It’s an example worth remembering.
In California, there are dozens of towns like Paradise that face a similar risk if a disaster forced residents to flee, according to an analysis published this week. From Bay Area cities to Central Valley towns, more than 100 places in the state made the list.
The analysis, published by analytic firm Street Light Data, focused on places with populations under 40,000 across the U.S. Researchers determined the number of available exits in each place and used location data gathered from smartphone apps and GPS devices to calculate the most commonly used routes residents take to leave.
Each place was scored and ranked based on the number of people were also likely to take the main road during an emergency, resulting in traffic gridlock, said Laura Schewel, chief executive of Street Light Data.
“Our analysis shows that if you have a city where there are four exits but 90 percent of the trips all use one then in an evacuation that creates an unnecessarily dangerous bottleneck,” Schewel said. “If there are four ways out and everybody has the habit of taking the one then you can maybe change behavior.”
Evacuations will be less risky In towns where traffic is balanced across exits when disaster strikes versus the places where the majority of people are flocking to the same one, Schewel said.
Yet in some places, like flood-prone McKinleyville; the private suburban enclave Coto de Caza; and the waterfront city of Sausalito, more than half the residents take the main exit even though there’s three or more.
In South Lake Tahoe, which has 9 nine exits, people took the main road about 48 percent of the time. In nearby Kings Beach, another popular tourist destination, there are 5 exits and residents use the main road about 47 percent of the time.
Other communities on the list like Knight’s Landing, Bell Canyon and Lompico are restricted to two ways in or out.
Schewel said the analysis is designed to offer another layer of insight but it’s not a solution.
“Evacuation preparedness is really complex. This is not a magical big data solution telling these professionals what to do,” Schewel said. “It’s just one piece of a complicated puzzle.”