GERMAN drivers would have been surprised in 1995 to see an autonomous, high-end Mercedes-Benz streaking down the autobahn at more than 160km/h.
The S-class Mercedes was driverless; they shouldn't have been.
 
Robotic vehicles have been tested on public roads and specialised test tracks since the late 1970s as scientists and car makers chase technology ultimately expected to make drivers passengers in their own cars.
 
Technology developed for the 1995 Mercedes test has evolved over time and formed the sophisticated active cruise control feature now installed in production S-Class vehicles from the German marque.
 
However, the gap between present-day active cruise control and the autonomous Mercedes of 1995 is large.
 
And the gap between that Mercedes and vehicles that can navigate suburban streets without human assistance from either inside or outside the cabin is enormous.
 
Even though the road conditions in the 1995 Mercedes test were ideal - highways are considered the simplest environment for robotic vehicles - the furthest the car managed to travel without human intervention was less than 160km.
 
The University of Technology Sydney's Dr Sarath Kodagoda says it is difficult to predict when truly driverless cars will hit Australian roads, but robotics experts will have a better idea after November.
 
That is when autonomous car researchers from around the world will meet to compete with one another in an intricate test sponsored by the US Defence Advance Research Projects Agency (DARPA).
 
Entrants will be given five minutes to load a map into the computers that control their autonomous vehicles and then the cars will be expected to navigate a complex road course on their own.
 
The cars must be able to respond to traffic signs and signals, obstacles and complete tasks such as parking and three-point turns.
 
"Once (the DARPA challenge) is finished we will have a very good understanding of the real challenges we face," Kodagoda says.
 
Nevertheless, Kodagoda says it could be 15 years before autopilot systems suitable for use on open highways, let alone city roads, are commonplace in cars.
 
"I would think in 15 years there can be systems at least on highways, because highways are much more structured than the urban environment.
 
"But we might not see those vehicles everywhere in the world because there might be some legal issues around who is responsible for an accident if an autonomous vehicle is involved. Is it the owner of the car, or is it the person who wrote the software code?"