A Record Number of Google Autonomous Vehicles on the Roads. And Not A Single New Accident
By: Alice Corona
Tags: Self Driving Cars, Google Car, Data Journalism

At Silk, we’re curating a project that tracks Google’s reports and visualizes them in interactive maps and charts. Follow the project to get email notifications for every update.

Note: the date of incidents prior to June 2015 is approximate. Google only reported the month in which they occurred. So, for instance an incident reported for May 2014 will have 01/05/2014 as date.

Note: Silk has been discontinued as of Dec. 15th 2017 so links are broken and visualizations are static. Will replace them asap.

Every month Google is mandated to publish a report summarizing crash data and incident information for accidents involving Google Autonomous Vehicles (aka Google Cars). To date all crashes have been the fault of human drivers that struck Google Cars. In September, Google added 20 new vehicles to the fleet driving in public roads of Mountain View, California and Austin, Texas. Through the end of September 2015, there at total of 48 Google Cars out and about. That’s 20 more than were reported in the August, an increase of 71%. The fleet broke down to 34 Google cars driving in Mountain View and 14 in Austin. This is a record high since Google began reporting figures.

Despite this increase, there hasn’t been a single incident reported for the month of September. In fact, Google has been tweaking its robotic driving algorithms to better account for previous obstacles such as confusion over right-of-ways when meeting cyclists at intersections.

Because of the added number of cars and the lack on new incidents,, the per-mile-driven accident rate dropped to 7.5 per 1,000,000 miles from the 7.9 per 1,000,000 miles of August.

To put this in perspective, Google Cars have an accident rate that is roughly 2.5 times the national rate for “property-damage-only crashes”, as reported by the National Highway Traffic Safety Administration. However, most experts believe very few of the millions of minor accidents end up in NHTSA reports so Google Cars may in fact be outperforming human drivers when this is taken into account.

Over half the accidents occurred when a human driver was controlling the Google Car.

Only eight of the 16 total incidents occurred when the car was engaged in autonomous mode. Of the remaining, in six the car was in manual driving mode and in two the car was initially in auto mode, but the driver was able to take manual control of the wheel as the other vehicle approached. Human intervention might not be possible in the future. Google’s wants to build a car “without a steering wheel or pedals”.

According to Google, every accident was the fault of the driver of the other vehicle. What’s more, 13 of the 16 incidents involved another car hitting the Google car from behind.

The type of events described in the report seem to indicate that self-driving technology wasn’t the cause of the crash. On the contrary, they imply that a human error on the part of the driver of the other car was the likely cause of the accident. With the number of miles driven continue to increase and the exposure of Google Cars to public roadways continuing to increase, it is looking more and more like Google Cars will actually make our roads safer by taking human drivers away from the wheel and preventing them from rear-ending other drivers or causing other sorts of accidents.

While Google’s AV technology seems well sophisticated for public streets after more than 2 years of testing, the car itself might still need improvements. In almost all the crashes, 14 out of 16, it was the Google car that reported some damage. The other car, which likely caused the accident in the first place, was damaged only in two instances