The two bicyclists killed last week — on the same day — in separate incidents by speeding motorists caused shock and dismay. But there was something more.

Anger.

“People are furious,” said Chris Cassidy, communications director for the Bicycle Coalition. “Two women dying in one day — biking legally and wearing helmets — is unprecedented. We are not seeing that city leaders care enough to take action. It feels like a lot of hollow talking points.”

Of course, that’s what you’d expect from an advocacy organization. But the reality is that city leaders are upset.

Mild-mannered Mayor Ed Lee was nearly shouting at a press briefing last week.

“We are simply outraged,” he said. “These aren’t accidents. They are tragedies that can be prevented.”

Municipal Transportation Agency Director Ed Reiskin, who was also at the press conference, said that roughly 30 people are killed on the streets each year by motorists.

“We are no longer accepting as fact that people need to die on the streets of San Francisco,” he said. “We believe speeding was involved in both collisions, so speed enforcement is one of the most powerful things we can do.”

But we can’t put a cop on every corner.

There is, however, an answer. It’s a proven, effective way to reduce speed and decrease accidents and fatalities, and it could be installed in San Francisco cheaply and quickly.

The official name is “automated speed enforcement,” but the simplest way to think of it is “speeding cameras.” The self-activating cameras photograph speeding vehicles. Like red-light cameras, they can automatically generate and send a citation to the violators.

More than 140 communities across the country already have the cameras, and the results are irrefutable. According to a report generated by Vision Zero SF, the city’s safe street policy agency, Portland, Ore., saw a 30 percent decrease in speeding vehicles after cameras were put to use in 2009. Chicago’s speeding-vehicle numbers went down 31 percent after installation in 2013.

In Washington, D.C., perhaps the closest parallel to a congested urban center like San Francisco, there was a 70 percent reduction in fatalities and a 60 to 80 percent drop in speeding violations within two months of camera deployment. Washington installed the first stationary speed camera in the nation in 2005.

“I think (camera installation) is a no-brainer,” Reiskin said. “The National Highway Traffic Safety Administration has found that the use of speed cameras can reduce incidence by 25 percent. It’s working.”

So when do we install the cameras? Not so fast. There are hurdles, not the least of which is that the state Legislature would have to take action: Enforcement by speed cameras is specifically prohibited under the California Vehicle Code.

Local state representatives like Assemblyman David Chiu support automated enforcement, but as he says, this isn’t the first time it’s been proposed. According to the city controller’s report on automated speed enforcement, “Since 2007, 16 bills ... have been introduced in the California Legislature,” and all failed.

As Walk SF Director Nicole Ferrara says, “It sounds like a fantastic idea to San Francisco, but Sacramento is a different ballgame. It has a lot more auto-centric constituents.”

The objections range from the “slippery slope” privacy argument — first they put in speeding cameras and next, Big Brother will be videotaping us everywhere — to claiming this is nothing more than a money grab.

But the cameras activate only when a car is going 10 mph over the speed limit. And the lens focuses on the rear license plate, so it doesn’t show who is driving the car.

As for the money grab, the idea is to keep the fines relatively low. While running a red light can cost over $400, a speeding citation would be more like $100.

“This will not be criminal or punitive,” Reiskin said. “There will be no points on your driving record and relatively low fees — lower, I believe, than if you were pulled over by a cop.”

Unfortunately, the window for new legislation has nearly closed, so it’s unlikely anything will be proposed until the new year. In San Francisco, where the frustration is growing, groups like the Bicycle Coalition say the sooner the better.

A blog post about the fatal accidents last week went up on the coalition’s website Friday. By Monday morning, there were 1,000 responses. That only reinforces the commitment of someone like Chiu, a regular bike rider, who recalls being knocked off his bike once when a driver opened a car door in front of him.

“Our streets are not safe,” Chiu said. “And I am saying that from personal experience.”

It’s time to do something about that.

C.W. Nevius is a San Francisco Chronicle columnist. His columns appear Tuesday, Thursday and Saturday. Email: cwnevius@sfchronicle.com Twitter: @cwnevius