Volvo is about to test out a group of 100 self-driving SUVs on the streets of London sometime in 2018, but the average pedestrian would no be able to tell them apart from regular cars; they would be completely unmarked.
As Erik Coelingh explained to the Observer, this is to prevent human drivers from attempting to mess with the autonomous vehicles. “I would expect they will, but I don’t know how and to what extent. So just to be on the safe side they will all be unmarked cars. I’m pretty sure that people will challenge them if they are marked by doing really harsh braking in front of a self-driving car or putting themselves in the way.”
This statement is not exactly unfounded; a London School of Economics study found that many human drivers are looking forward to bullying autonomous vehicles, since their software would try their best to avoid collisions and drive as safely as possible. As one driver said in an interview for the survey, ““I’ll be overtaking all the time because they’ll be sticking to the rules.”
The decision to make the cars unmarked is probably for the best; Volvo doesn’t want to tempt the more aggressive drivers on the road, and the unpredictable nature of such drivers would severely skew the test results.