Driving fast is hard. It's also scary. At least according to Google, who in a recently released report detailed the reasons that their custom-designed self-driving cars currently top out at 25 miles per hour. It appears that traveling at the slower speed is simply easier for the cars to manage, while simultaneously it makes them appear less threatening to a perhaps wary public.
The issue of the autonomous cars' speed was on everyone's mind last month, as one of Google's (Alphabet's) Pixar-like self-driving cars got pulled over by a Mountain View motorcycle police officer for traveling 24 mph in a 35-mph zone. It seems the car had caused a traffic backup.
Google's monthly report on the self-driving car project goes into detail as to the thinking behind the company-placed speed limit.
"First, slower speeds were easier for our development process," states the report. "A simpler vehicle enabled us to focus on the things we really wanted to study, like the placement of our sensors and the performance of our self-driving software. Secondly, we cared a lot about the approachability of the vehicle; slow speeds are generally safer (the kinetic energy of a vehicle moving at 35mph is twice that of one moving at 25mph) and help the vehicles feel at home on neighborhood streets."
Overall, the take-it-slow approach looks to being paying dividends, as the report notes that the self-driving cars have "been involved in 17 minor accidents during more than 2 million miles of autonomous and manual driving combined," but that "[not] once was the self-driving car the cause of the accident."
It appears that while the reality of autonomous self-driving Google cars shuttling you around town is approaching faster than we all thought, it may move quite slowly when it finally gets here.