'Don't jump in front of driverless cars for fun' and other tips for sharing the roads with driverless cars

The rest of us can learn from San Francisco residents about what it's like to share the roads with driverless test cars.

General Motors' Cruise and Google sibling Waymo operate driverless taxis in San Francisco. The city is one of America's first major population centers where it's normal to see computer-piloted cars without a human in the driver's seat.

Some San Franciscans told my colleague Heather Kelly that they feel unsafe around the driverless test vehicles. Others said they are more comfortable sharing roads with driverless cars than they are with unpredictable human drivers.

Now, driverless test cars are also operating in parts of the Phoenix area, Austin and Los Angeles. It is not clear where driverless test cars might arrive next.

With Heather's help, I put together a rundown of what you need to know if driverless test cars come to your neighborhood soon.

Where I live in New York, city officials have mostly kept driverless test cars off the streets. When I visit San Francisco, I feel unnerved seeing driverless test cars but also grateful.

I'm outraged at the catastrophic number of deaths and injuries on America's roads. I hope that driverless cars can be part of the solution. (Although there are proven approaches to cutting traffic deaths today and we're mostly not doing them.)

You and I can hope driverless cars will make roads safer in the future andwe can want autonomous vehicles to be as safe as possible during a development phase that might last for decades.

Here are six pieces of advice for sharing roads with driverless test cars. I'll also say that it's nuts that youmust adapt to a potentially deadly and half-baked technology in our public spaces rather than the other way around.

1. Don't jump in front of driverless cars for fun

Yes, this needs to be said.

Cruise and Waymo confirmed to Heather that people intentionally throw themselves in front of moving driverless cars. Just don't.

2. Expect driverless cars to be overly careful

Driverless cars are largely programmed to obey the rules. They drive the speed limit and will probably be the last to move ahead at a four-way stop.

The absence of aggression can be wonderful compared to human drivers. The caution can also be dangerous or annoying.

Heather said that when she rode in a Waymo test vehicle, a human-driven car was making a three-point turn and waited - and waited and waited - for the Waymo car to go past. The driver eventually made her turn.

3. Be extra careful in unusual situations

Driverless cars can freeze or even crash when they encounter something unexpected that a human might manage easily.

After storms in the Bay Area, at least one Waymo car stopped in the middle of an intersection where there was a small downed tree, Heather wrote in her article. But it was safe to drive over or around it.

4. Social cues won't work with computers

You can't make eye contact with a driverless car at an intersection for a gut sense of whether it's going to barrel ahead. You can't wave your hand to make sure the car will yield to your family in a crosswalk.

Instead of those familiar social cues, the "alternative is blind trust in a hulking piece of metal and programming," Heather said.

Phil Koopman, a Carnegie Mellon engineering professor who has worked on autonomous vehicle technology for 25 years, advised being extremely careful when you're crossing in front of a driverless car without someone ready to take over the wheel - even if the car is stopped at a red light.

5. Know how to reach the companies

The extremely online residents of San Francisco love to post videos of driverless cars that have mysteriously stopped in the road. Heather said that you can contact Cruise or Waymo to report a wayward car.

6. Test out a driverless car yourself

The first time Heather took a Waymo driverless taxi ride, she found it terrifying at first and then she started to feel more confident.

At one point during her trip, a human-driven car came speeding around a bend on a relatively narrow road. Her Waymo test car braked and moved slightly to the side of the road and kept them out of harm's way.

"The longer we drove I started to have more trust," Heather said.

Let's step back: No one asked your consent

The hope is that short-term glitches and potential safety risks of today's driverless test cars are worth it to make roads safer from drivers who speed, get distracted or drive drunk.

But even if driverless cars will be safer than the status quo - and Koopman said this hasn't been proved yet - we can still want stricter controls to minimize their risks.

California regulations allow approved driverless vehicles to operate without a human in the car to intervene if something goes wrong. San Francisco officials want to slow the spread of driverless cars after what they say have been public safety risks from test vehicles that have interfered with firefighters, rear-ended a city bus and caused needless calls to emergency services.

Koopman told me that Waymo has a reputation for being methodical and conservative and may deserve more trust than other driverless car companies. Mostly, though, he believes that driverless cars shouldn't be allowed to ditch human backup in vehicles until they have a proven safety record and that companies should be forced to comply with industry standards for human test drivers.

Not doing so puts our lives at needless risk, he said.