San Francisco wants robot-car makers to demonstrate their vehicles to public safety personnel before cars without drivers hit city streets.

“I am specifically requesting that all (autonomous vehicle) manufacturers who intend to apply for a driverless testing or deployment permit participate in a safety assessment exercise in San Francisco,” Mayor Mark Farrell wrote in a letter addressed “Dear Autonomous Vehicle Manufacturers” and sent Thursday.

The point of the voluntary program is for robot-car makers to show their vehicles’ safety features and to make sure that San Francisco first responders, transit operators and other city staff know how to interact with the no-driver cars in case of an emergency.

“This is the future of driving in our country and here in San Francisco,” Farrell said in an interview. “I’m very supportive. As the industry evolves, as mayor, public safety is my first concern.”

Farrell said he had personally called several companies already and received positive reactions to his request. Makers of self-driving cars “want (them) to be known as the safest vehicles on the street,” he said. “My hope is that everyone we ask will participate in this program.”

If companies refuse, San Francisco has no authority to ban their no-driver cars from operating here, he said.

The Department of Motor Vehicles issued regulations late last month allowing companies to apply to test cars without backup drivers, and said it could begin issuing permits for driverless tests by April 2. Some 50 companies, almost all in the Bay Area, already have DMV permits to test autonomous cars with backup drivers ready to take control.

The DMV and industry sources said they expect several companies will want to apply early for the no-driver testing permits.

DMV rules for no-driver cars include notifying cities before driving the cars within their bounds, and providing a plan to interact with law enforcement.

Waymo, a sister company of Google that has been a pioneer in the autonomous vehicle industry, said it would like to eventually test and operate truly driverless vehicles in California; that it believes in working with public safety officials; and has already talked to San Francisco about setting up first responder training.

Farrell said he envisions a big “demo day,” at which the first companies to apply for no-driver permits would show off their vehicles to key personnel from police and fire departments, California Highway Patrol, parking control and transit operators.

While the first such day could happen by the end of this month — and Farrell hopes to attend — it would be an ongoing process as companies continue to apply for driverless testing and, eventually, operation with paying passengers.

Among issues to cover: showing where important documents will be stored; providing training on the cars’ features, technology and systems; and demonstrating how they will work when surrounded by pedestrians, bicyclists and Muni buses.