Would you ride in a car with no driver?
Google is trying to make a self-driving car.
Despite progress over the past year, the cars have plenty of learning to do. Google hopes to get the technology to the public in 2017. Others believe it's more likely to take until 2025.
Google's self-driving cars already can drive on freeways. Human drivers would be expected to take control if the computer fails. Eventually, Google says, there would be no need for a driver. Passengers could read, daydream or sleep. They could even work while the car drives.
But for now, Google is focused on the common tasks of city driving.
To deal with people on bikes, engineers have taught the software to predict what people on bikes are likely to do. The software plots the car's path accordingly. Then it reacts if something unexpected happens.
While the car knows to stop, knowing when to start again is still a challenge. This is partly because the cars are programmed to drive defensively. At a four-way stop, Google's cars have been known to wait in place as other cars edge out into the intersection.
The cars still need human help with other problems. Among them, understanding the gestures that drivers give one another to signal it's OK to merge or change lanes, turning right on red and driving in rain or fog. These tasks requires smarter sensors.