Google has shed some light on why one of its driverless cars was stopped by police for driving too slow last month, an incident that attracted widespread attention as the vehicles continue to capture the public's imagination.
Google's driverless car was stopped by police in California in a curious incident – moving at a speed of 24 miles per hour (mph) in a 35 mph zone.
The firm does not send its self-driving car on roads with a speed limit above 35 mph. In its monthly report on its autonomous vehicle project, Google explained why.
"First, slower speeds were easier for our development process. 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," Google's report said.
"Secondly, we cared a lot about the approachability of the vehicle; slow speeds are generally safer (the kinetic energy of a vehicle moving at 35 mph is twice that of one moving at 25 mph) and help the vehicles feel at home on neighborhood streets."