Self-Driving Car Safety: A Comprehensive Analysis

The safety of self-driving cars is a topic of significant interest and discussion. This article provides a detailed look at the accident rates and malfunction statistics of self-driving cars, highlighting the differences across various autonomous driving levels and companies.

Accident Rates in Autonomous Driving

Zero is the number of accidents reported out of all miles driven by Waymo One's fully autonomous vehicles in real-world operations. Over the years, the Waymo One system has logged 6.1 million miles on the road with just 18 accidents reported.

For comparison, the national average is one accident in 484,000 miles. Waymo's statistics show that the rate of crashes for their autonomous vehicles is significantly lower, at one crash per 338,888 miles of driving. This data gives a clear indication of the safety and reliability of these vehicles when operated autonomously.

Tesla's Advanced Autonomous Driving Technology

Tesla offers a highly advanced Level 2 self-driving feature called Autopilot. Tesla recently reported that for Q4 2021, there was "one crash for every 4.31 million miles driven" where drivers were using Autopilot, Autosteer, and active safety features.

Comparing Accident Rates Across Brands and Models

It's important to note that these statistical values are not directly comparable because they do not account for all factors, such as the condition of the vehicles, the types of roads driven, and weather conditions. For example, Waymo cars are better maintained and driven on less problematic roads. Tesla's Autopilot system is more commonly used on roads with fewer intersections, which are areas where most accidents typically occur.

Additionally, the weather conditions are vastly different. Waymo's autonomous vehicles do not operate in bad weather, whereas Tesla's Autopilot system has limited capabilities in inclement weather.

Current State of Autonomous Vehicles

There are no self-driving cars in full production use today. The closest to commercial use are the Waymo One vehicles used by 400 families in Scottsdale, Arizona. All other self-driving vehicles on the road are prototypes undergoing extensive testing. These prototypes are expected to malfunction frequently, and there is no well-defined standard for understanding the frequency of interventions required.

The California Department of Motor Vehicles (DMV) requires testing companies to report how often their autonomous vehicles need intervention. However, the reported numbers range widely, with some vehicles needing intervention more than once per mile to every 12,000 miles.

Human Safety Drivers and Crash Prevention

The primary reason for the low accident rates in autonomous vehicles is the presence of human safety drivers who intervene when necessary. Better companies track when their vehicles would have crashed due to failure, but this information is not commonly published.

Pushing the Boundaries of Safety

Dependent on the interpretation of 'times', accidents can be measured on a per-mile or per-hour basis. Tesla reported that drivers of their vehicles had driven 1 billion miles on Autopilot. Over the past quarter, they registered "one accident or crash-like event for every 3.34 million miles driven" with Autopilot engaged. Assuming an average speed of 50 mph, this translates to one accident every 66,800 hours, or approximately 0.0015 times out of 100.

Current statistics show that driving autonomously with advanced self-driving technology is currently between 3 and 7 times safer than driving yourself.