FRANKFURT (Bloomberg) -- Automakers and suppliers are rolling out systems that take over the wheel from the driver and pilot the car in situations such as when traffic slows to a crawl, finding a space in a crowded garage, or squeezing into a tight parking spot.

Daimler's Mercedes-Benz, BMW, Nissan and Volvo, along with suppliers Robert Bosch and Continental, are among companies working on autonomous driving technology.

Mercedes is leading the way with an add-on called "Stop&Go Pilot" available in its top-of-the-line S-class sedan.

Backed by an array of 12 ultrasonic detectors, five cameras and six radar sensors, the 79,800-euro ($105,800) S-class can match the speed of the car in front of it, even coming to a complete stop and steering to stay in the lane. The feature costs 2,678 euros in Germany.

Sitting back to read emails or watch a video as the car takes you to your destination -- a scenario envisioned by the likes of Google -- is years away. But the Mercedes option and others being readied by rivals such as BMW and Volvo Cars show that the roll-out is under way.

"Autonomous drive won't come as a revolution overnight," said Jochen Hermann, director of driver-assistance systems at Mercedes. "The driver needs to get used to the technology."

Though it will be hard to swallow for some motoring purists, the machine might actually be the better driver. More than 90 percent of auto accidents result from human error, according to Germany's traffic research institute BASt. The group estimates that the German economy suffered more than 30 billion euros in damages from traffic accidents in 2010, the latest data available.

Avoiding dents

"If individual mobility is to survive, automated driving is imperative," said Peter Fuss, a partner at consultancy Ernst & Young in Frankfurt. "It's the only way to prevent traffic jams and ensure road safety."

Like the Mercedes stop-and-go system, other pending auto- pilot features are geared toward handling the drearier bits of the daily commute.

In November, BMW plans to introduce an upgraded parking-assistant option in the 5 series that allows hands-free driving as the car turns independently into a parking space, helping to avoid dents.

Robert Bosch, the world's largest supplier of auto parts, showed a similar feature at its headquarters in Stuttgart, Germany, in April when a driverless car reversed into a parking spot as if by remote control.

Volkswagen Group's Audi is developing a system that allows the driver to exit the car at the entrance of a parking garage, leaving the vehicle to find a vacant spot on its own.

Toll booths

Volvo Cars is working on a similar parking-garage feature and will introduce an automatic brake technology that can detect obstacles in the dark in the new XC90 next year.The sport- utility vehicle can also keep the car on the road through a system that senses where the pavement ends.

BMW and Continental, Europe's second-largest maker of car parts, are collaborating on technology to master more complicated situations such as toll booths, road works and driving across national borders.

Continental is spending more than 100 million euros on assisted-driving efforts this year and has 1,300 engineers involved in development. "To do something that reduces casualties can't be wrong," said Ralf Lenninger, Continental's head of interior development. "Our aim is fully automatic driving that allows the driver to watch TV."

Nissan Motor plans to sell affordable self-driving vehicles by 2020, Executive Vice President Andy Palmer said this week.

Red light

One of the biggest hurdles is legislation. To comply with existing rules in Europe, the Mercedes system only allows the car to keep control at speeds of less than 10 kilometers (6 miles) per hour. At higher speeds, the system continuously monitors the driver and makes sure she keeps her hands on the steering wheel, letting go for more than about 10 seconds prompts a red light to flash and then a beep to sound.

"We don't want the driver to believe the system can do everything, because at the end of day, the driver is still responsible," said Mercedes's Hermann. While the goal is to eventually have fully autonomous vehicles, the roll-out of the technology is focused on "taking pressure off the driver in situations that aren't fun," he said.

The stop-and-go feature is activated by switching on cruise control. It shuts off when the driver steps on the brake or switches it off manually.

Planes, trains

While auto pilots have been used for decades in planes, trains and ships, these highly trained vehicle operators work in structured traffic patterns and don't have to worry about children darting into their path.

Concerns about reliability in street traffic are reflected in Nevada. While the state allows testing of highly automated prototypes on public roads, a licensed driver must be ready to take control in case the system fails.

"The operation of the automated drive systems have to be idiot proof to exclude errors," said Richard Viereckl, a partner with consulting company Management Engineers at Booz & Co. in Dusseldorf. "It's going to take quite some time before we can sit on the back seat and sip cocktails, and let the car drive us home."