Would you share the roads with a car that was driving itself? Several Japanese drivers already have, as Nissan has completely its first public highway test for an autonomous vehicle.

The Nissan Leaf electric car successfully negotiated a section of the Sagami Expressway in Kanagawa prefecture, southwest of Tokyo, with two important passengers on board--the prefecture's Governor, Yuji Kuroiwa, and Nissan Vice Chairman Toshiyuki Shiga. The test drive--which took place entirely automatically on the highway--was carried out with the cooperation of the Kanagawa prefecture.

MUST SEE: 2015 Ford Mustang: The Real Thing, Leaked (Some More)

Called Autonomous Drive, Nissan's system is able to detect road conditions and automatically operate the vehicle's main controls. Steering, braking and acceleration can all be controlled autonomously, and the vehicle is able to respond to several scenarios once out on the highway. The Autonomous Drive Leaf can follow vehicles and maintain a safe distance, change lanes, overtake, merge and exit highways, and negotiate interchanges--covering most aspects of highway driving.

Nissan has already stated its intent to offer an autonomous car for sale by 2020--one of several automakers to explore the technology, hoped to reduce congestion, fuel consumption and accidents compared with today's levels.

ALSO SEE: Fast & Furious Star Paul Walker Dies In Fiery Crash, Authorities Investigating

Unusually, the company also intends to offer the technology across its range, rather than limit it to the most expensive models. This suggests that, like some other autonomous vehicles undergoing testing, it will be a part-time system--taking over in emergencies or handling the more mundane aspects of driving, such as freeway trips.

Shiga says the project points the way to "a safer, more comfortable and environmentally-friendly mobile future".