Mill Valley Evacuation Planning and Preparedness

On March 15, 2021, Vice-Mayor McCauley and Staff presented a report to Council and the Community on Evacuation Planning and Preparedness. Vice-Mayor McCauley highlighted over the last several years, he had been working on gaining a detailed understanding of the time necessary to complete a full-scale citywide evacuation in the event of a large fire associated with the Mill Valley City and County areas. During this time, Vice-Mayor McCauley thought creatively outside of the norm and tapped into resources and contacts he had with tech giant Google. As this sparked their interest, this further lead to a significant project with Google Research.

Following a series of meetings and calls, Google Research committed resources to further study the dynamics and timing involved in a city-wide evacuation. The group conducted a study of Mill Valley and the City of Paradise, which was then developed into an academic paper for publication in a highly respected peer-reviewed global technical journal, Transportation Research Interdisciplinary Perspectives. The recently published paper can be found at:

The Google Research Group developed a detailed simulation of the City’s 6000-plus households attempting to leave town in their cars using home locations and road capacities under various conditions, including speed of notification, the timing of departure, and other variables. Based on the research and simulations, the Google Research Group further studied potential ways to improve the speed of an evacuation plan. The City’s team was allowed to review the draft document and offer comments before publication. The team’s review of Google’s simulation provided two critical insights.

The first being the concept surrounding contraflow traffic (opposite traffic direction) on E. Blithedale Avenue in the event of an emergency, with all inbound and outbound lanes exiting out toward the freeway. The second insight is that each household only utilizes one vehicle to evacuate during an emergency.

Staff further took this information and presented on the following vehicle routing options during an evacuation:

  • Miller Avenue – Two lanes of outbound traffic from Millwood to Willow
  • E. Blithedale Avenue – Two lanes of outbound traffic from Roque Moraes to Ashford
  • Hamilton Drive- Two-Way traffic with access to HWY 101

Along with these identified vehicle routing alternations, City staff is further exploring the concept of vehicle staging areas during an evacuation. In response to observing the evacuation traffic simulations first-hand as run by Google Research, the City team further investigated an additional priority of preventing downstream backups on arterial roads, which potentially delay evacuation timing for vehicles exiting from the canyon and hillside neighborhoods.

Each vehicle staging area, such as Bay Front Park or Tamalpais High School fields, could temporarily store up to 2,000 vehicles. This would remove these vehicles from the potentially gridlocked roadways and clear the way for those people fleeing in cars stuck in traffic in the canyons. Vice-Mayor McCauley noted ‘It’s like a crowded grocery store opening more check-out stands to quickly clear a customer backup.’ Additionally, if the freeways are gridlocked due to a more county-wide event, our citizens have a place to safely go.

Deputy Fire Chief Tom Welch delivered important information on our identified Community Refuge Areas, which are pre-identified areas throughout the Mill Valley and Southern Marin region where residents can seek shelter from a fast-moving wildfire within their neighborhood. Widely considered as an area of last resort, CRA’s provide community separation from fire and provide relative safety for 60 to 90 minutes until law enforcement provides direction. Typically, large, green open spaces like golf courses, parks, and ball fields, CRA’s are provided as options when complete evacuation is not possible due to roadway inundation or blockages. Some identified CRA’s within Mill Valley:

  • Old Mill School
  • Mill Valley Golf Course
  • Mill Valley Middle School
  • Tamalapis High School
  • Hauke Park

If you are looking for further information on emergency preparedness or viewing the report and presentation, please visit

We look forward to a collaborative effort between public safety and the Mill Valley community on a 2021 Evacuation Drill, TBD.