Los Angeles - Although you can't yet buy a self-driving car, the technology's long and windy road to market is getting shorter. Nevertheless, manufacturers need to perfect the technology before releasing it for everyday motorists, and that means more of the road testing that began several years ago.
Now California's department of motor vehicles has proposed rules from 2018 will govern how ordinary people can get robocars. That's a big step forward for regulations that were first discussed more than four years ago, first drafted in December 2015 and then substantially redrafted to accommodate carmakers' concerns.
Several other states are also moving to get autonomous vehicles into the hands of their residents - so what do we need to know about these cars of the future?
Is the technology safe?
Safety is paramount, both as a selling point and a potential liability.
Traditional car companies and Silicon Valley upstarts are trying to teach cars to drive in different ways, but all agree that cars that don't drink, text, fall asleep or drive erratically can save thousands of lives. If the technology were reliably better than human drivers, however, it would be nearing a launch which most companies say is a few years away.
At the same time, in California alone the 42 companies with testing permits have been logging hundreds of thousands of kilometres on nearly 300 prototypes with few crashes that were clearly the technology's fault. That testing requires a trained safety driver behind the wheel, just in case the onboard computers and sensors fail. States including Arizona, Michigan and Texas, also have hosted testing.
Unlike earlier versions of the California regulations, the current proposal would follow the lead of the federal government, which wants to let companies self-certify the technology is road ready. That is the same approach as human-driven cars, to which consumer advocates retort that such a huge leap in technology should require outside scrutiny before its public launch.
What will the first driverless cars look like?
A lot like the cars on the road today.
Though some companies have experimented with cars that don't have a steering wheel or pedals, those kinds of advances are probably several years beyond the first models. The reasons are both practical and about perception: The cars may still need a human backup to take control in emergencies, plus the general may not be ready to hand over total control to a machine.
When will these car be available?
Customers probably won't be able to walk into a dealership and buy a fully driverless vehicle in 2018. Major automakers such as BMW, Ford, Mercedes, Nissan and Volvo have all said it will be closer to 2020 before those vehicles are available, and even then, they could be only for ride-hailing fleets and other shared applications.
Tesla says the cars it's making now have the hardware they need for full self-driving. The company is still testing the software and won't make it available to owners without government approval. Waymo, formerly Google Cars, isn't commenting on its rollout schedule.
It's also possible, if not likely, that autonomous driving will reach the market not as a car that one person owns but rather a shared vehicle that riders can summon with an app or subscription.