Google experts offer insight on fire evacuation

A Google computer program that simulated a wildfire evacuation in Mill Valley is offering solutions to ease traffic congestion in an emergency.

Researchers Yu Chen, Yusef Shafi and Yi-Fan Chen compared Mill Valley’s infrastructure issues to the town of Paradise, which was nearly leveled by the Camp wildfire in 2018.

In their report, researchers built a traffic simulation to explore how to avoid the bottlenecks that happened in Paradise, where at least 85 people were killed.

“We apply the pipeline to two case studies in California,” the report said. “The first is Paradise. … The second is Mill Valley, which has high risk of wildfire and potential traffic issues since the city is situated in a narrow valley.”

There are two major roads in and out of the Mill Valley, which for years has kept emergency evacuation a top priority for the city of about 14,000 residents.

The effort to get Google to use the city as a model was led by Vice Mayor John McCauley, who said he contacted a senior financial executive at Google to find out if the tech giant would study large-scale evacuation planning in Mill Valley.

A virtual model was developed to help the city come up with better evacuation plans. It simulated residents of the city’s 6,000 households getting in their vehicles and trying to escape the city at once.

The number of simulated vehicles was 23,635 for Paradise and 12,212 for Mill Valley, according to Google’s report.

“This is the first time this kind of data has been developed, as far as I can tell,” McCauley said. “And we are thrilled to be chosen as the city to model this potentially groundbreaking information.”

He said the study found evacuation times would be reduced by one hour if residents only took one vehicle. He said the city will be pushing this message to the community.

“So save those behind you,” he said. “Take just one car because your cars are insured. If you only have one car we will all get out faster and it’ll be safer for all of us.”

Another solution derived from the Google team is called “contraflow,” he said.

Police Lt. Lindsay Haynes said “contraflow” is when traffic moves in a direction that’s not designated. She said it was used in Santa Rosa and Paradise.

“So essentially traveling in the opposite lanes of traffic in order to increase evacuation flow,” Haynes said.

The method would be used on the two main routes in the city, East Blithedale Avenue and Miller Avenue, to get people to Highway 101.

The city owns a trailer with traffic evacuation equipment such as signs, barricades and cones. Two more trailers will

be purchased this year for $15,000, the city said.

The Google report was presented at the the City Council meeting on March 15. Residents called and wrote into the meeting to point out that there is another way out of the city, through Edgewood, Molino and Montford avenues.

Resident Ronald Schafer wrote that evacuees in Homestead Valley could create a bottleneck on the Edgewood system.

“Any delay due to blockage will endanger the evacuees remaining on the upside of the hill and is of major concern to all of us who cannot freely drive out,” he said.

McCauley said Bayfront Park could be used as a vehicle staging area to relieve gridlock and allow vehicles in the canyons and hillsides to escape.

“The strategy of intermittently moving cars to Bayfront Park is like a grocery store opening extra checkout lanes to move customers more efficiently,” he said.

Bayfront Park could hold up to 1,000 vehicles. Tamalpais High School sports fields could hold another 1,500 vehicles.

Fire officials said if roads become blocked then residents should get to the nearest “community refuge area.”

“We identified certain areas that were less combustible and that the community could exit to should the need arise under under lastresort type conditions,” said

Deputy Chief Tom Welch of the Southern Marin Fire Protection District.

The largest refuge area is the Mill Valley Golf Course. The city staff is reviewing the cost related to converting some of these refuge areas into vehicle staging areas.

McCauley said the city ought to conduct an evacuation drill this summer.

“It won’t be that hard,” he said. “Let’s do it and see operationally how it how it goes. So that’s something I’m really lobbying for us to do.”