Very soon, cars will be able to drive themselves for long stretches on the highway, but what happens when the car needs you to take the wheel? At a Bosch-sponsored event in Germany, the automotive equipment supplier showed off a solution that works in a similar way to current navigation systems in cars. 

I sat in the passenger seat of a heavily modified Tesla Model S, while a Bosch test pilot took the driver seat for a demonstration on the company's test track near Frankfurt, Germany. As the car approached a section of road where it was allowed to self-drive, the center screen counted down the distance. Once in the zone, the driver pushed two buttons on the steering wheel, then let the car do the driving.

As the car came to the end of the approved self-driving zone, the screen began to count down the distance to when the driver needed to take back control, showing and sounding alerts as we got closer. It struck me that the information shown on the screen was similar to how navigation systems show the distance to the next turn, something most drivers will find familiar.

This capability represents the next step in driver assistance, what engineers call Level 3 self-driving, where humans share control with the car. This type of self-driving system is a natural evolution from current adaptive cruise control systems, which can regulate the car's speed in relation to traffic ahead. Along with adaptive cruise control, cars increasingly come with lane keeping systems that use cameras to recognize lane lines, and steer the car to prevent it from drifting into another lane.

To enable Level 3 self-driving, cars will contain high definition maps of specific roads. Automakers and their technology partners will create those maps, and wirelessly update them to existing cars. When the car drives onto a mapped road, it will be able to take over the driving. The car's computer continually compares what its sensors see with its stored map. Cadillac recently demonstrated its Super Cruise technology, using this methodology, which should become available in the next few years.

High definition maps won't be available for every road when this technology becomes available, however. Likewise, automakers may choose easier driving environments, such as highways and freeways, for self-driving rather than suburban or city streets. 

Imagine driving down I-5 on the west coast, I-95 down the east coast or I-80 across the country. After merging onto the freeway, your car tells you it can take over, so you let it drive for a couple of hundred miles to your exit, then take the wheel for the off-ramp. 

Of course, there's the problem of when the section of high definition mapped road runs out, and the driver doesn't take over. Bosch showed off a solution for that scenario as well. When the driver did not take the wheel after multiple audio and visual warnings, the car safely pulled over to the side of the road. 

Drivers in the near future may be waking up from a nap to find their car parked in a designated pull-over zone, refreshed but many miles down the road from their off-ramp.