arstechnica.com
Traffic safety After 50 million miles, Waymos crash a lot less than human drivers Waymo has been in dozens of crashes. Most were not Waymo's fault. Timothy B. Lee Mar 27, 2025 7:00 am | 59 A driverless Waymo in Los Angeles. Credit: P_Wei via Getty A driverless Waymo in Los Angeles. Credit: P_Wei via Getty Story textSizeSmallStandardLargeWidth *StandardWideLinksStandardOrange* Subscribers only Learn moreThe first ever fatal crash involving a fully driverless vehicle occurred in San Francisco on January 19. The driverless vehicle belonged to Waymo, but the crash was not Waymos fault.Heres what happened: A Waymo with no driver or passengers stopped for a red light. Another car stopped behind the Waymo. Then, according to Waymo, a human-driven SUV rear-ended the other vehiclesat high speed, causing a six-car pileup that killed one person and injured five others. Someones dog also died in the crash.Another major Waymo crash occurred in October in San Francisco. Once again, a driverless Waymo was stopped for a red light. According to Waymo, a vehicle traveling in the opposite direction crossed the double yellow line and crashed into an SUV that was stopped to the Waymos left. The force of the impact shoved the SUV into the Waymo. One person was seriously injured.These two incidents produced worse injuries than any other Waymo crash in the last nine months. But in other respects, they were typical Waymo crashes. Most Waymo crashes involve a Waymo vehicle scrupulously following the rules while a human driver flouts them, speeding, running red lights, careening out of their lanes, and so forth.Waymos service will only grow in the coming months and years. So Waymo will inevitably be involved in more crashesincluding some crashes that cause serious injuries and even death.But as this happens, its crucial to keep the denominator in mind. Since 2020, Waymo has reported roughly 60 crashes serious enough to trigger an airbag or cause an injury. But those crashes occurred over more than 50 million miles of driverless operations. If you randomly selected 50 million miles of human drivingthats roughly 70 lifetimes behind the wheelyou would likely see far more serious crashes than Waymo has experienced to date.Federal regulations require Waymo to report all significant crashes, whether or not the Waymo vehicle was at faultindeed, whether or not the Waymo is even moving at the time of the crash. Ive spent the last few days poring over Waymos crash reports from the last nine months. Lets dig in.Examining Waymos safety record since JulyLast September, IanalyzedWaymo crashes through June 2024. So this section will focus on crashes between July 2024 and February 2025. During that period, Waymo reported 38 crashes that were serious enough to either cause an (alleged) injury or an airbag deployment.In my view, only one of these crashes was clearly Waymos fault. Waymo may have been responsible for three other crashesthere wasnt enough information to say for certain. The remaining 34 crashes seemed to be mostly or entirely the fault of others:The two serious crashes I mentioned at the start of this article are among 16 crashes where another vehicle crashed into a stationary Waymo (or caused a multi-car pileup involving a stationary Waymo). This included 10 rear-end crashes, three side-swipe crashes, and three crashes where a vehicle coming from the opposite direction crossed the center line.Anothereight crashesinvolved another car (or in one case a bicycle) rear-ending a moving Waymo.A furtherfive crashesinvolved another vehicle veering into a Waymos right of way. This included a car running a red light, a scooter running a red light, and a car running a stop sign.Three crashesoccurred while Waymo was dropping a passenger off. The passenger opened the door and hit a passing car or bicycle. Waymo has aSafe Exit programto alert passengers and prevent this kind of crash, but its not foolproof.There were two incidents where it seems like no crash happened at all:In one incident, Waymo says that its vehicle slowed and moved slightly to the left within its lane, preparing to change lanes due to a stopped truck ahead. This apparently spooked an SUV driver in the next lane, who jerked the wheel to the left and ran into the opposite curb. Waymo says its vehicle never left its lane or made contact with the SUV.In another incident, a pedestrian walked in front of a stopped Waymo. The Waymo began moving after the pedestrian had passed, but then the pedestrian turned around and approached the Waymo AV. According to Waymo, the pedestrian may have made contact with the driver side of the Waymo AV and later claimed to have a minor injury. Waymos report stops just short of calling this pedestrian a liar.So thats a total of 34 crashes. I dont want to make categorical statements about these crashes because in most cases, I only have Waymos side of the story. But it doesnt seem like Waymo was at fault in any of them.There was one crash where Waymo clearly seemed to be at fault: In December, a Waymo in Los Angeles ran into a plastic crate, pushing it into the path of a scooter in the next lane. The scooterist hit the crate and fell down. Waymo doesnt know whether the person riding the scooter was injured.I had trouble judging the final three crashes, all of which involved another vehicle making an unprotected left turn across a Waymos lane of travel. In two of these cases, Waymo says its vehicle slammed on the brakes but couldnt stop in time to avoid a crash. In the third case, the other vehicle hit the Waymo from the side. Waymos summaries make it sound like the other car was at fault in all three cases, but I dont feel like I have enough information to make a definite judgment.Even if we assume all three of these crashes were Waymos fault, that would still mean that a large majority of the 38 serious crashes were not Waymos fault. And as well see, Waymo vehicles are involved in many fewer serious crashes than human-driven vehicles.Waymos get in fewer crashes than human driversAnother way to evaluate the safety of Waymo vehicles is by comparing their per-mile crash rate to human drivers. Waymo has been regularly publishing data about this over the last couple of years. Its most recent release came last week, when Waymo updated itssafety data hubto cover crashes through the end of 2024.Waymo knows exactly how many times its vehicles have crashed. Whats tricky is figuring out the appropriate human baseline, since human drivers dont necessarily report every crash. Waymo has tried to address this by estimating human crash rates in its two biggest marketsPhoenix and San Francisco. Waymos analysis focused on the 44 million miles Waymo had driven in these cities through December, ignoring its smaller operations in Los Angeles and Austin.Using human crash data, Waymo estimated that human drivers on the same roads would get into 78 crashes serious enough to trigger an airbag. By comparison, Waymos driverless vehicles only got into 13 airbag crashes. That represents an83 percent reductionin airbag crashes relative to typical human drivers.This is slightly worse than last September, when Waymo estimated an 84 percent reduction in airbag crashes over Waymos first 21 million miles.Over the same 44 million miles, Waymo estimates that human drivers would get into 190 crashes serious enough to cause an injury. Instead, Waymo only got in 36 injury-causing crashes across San Francisco or Phoenix. Thats an81 percent reductionin injury-causing crashes.This is a significant improvement over last September, when Waymo estimated its cars had 73 percent fewer injury-causing crashes over its first 21 million driverless miles.Insurance claims against Waymo are about 90 percent lowerThe above analysis counts all crashes, whether or not Waymos technology was at fault. Things look even better for Waymo if we focus on crashes where Waymo was determined to be responsible for a crash.To assess this, Waymoco-authored a studyin December with the insurance giant Swiss Re. It focused on crashes that led to successful insurance claims against Waymo. This data seems particularly credible because third parties, not Waymo, decide when a crash is serious enough to file an insurance claim. And claims adjusters, not Waymo, decide whether to hold Waymo responsible for a crash.But one downside is that it takes a few months for insurance claims to be filed. So the December report focused on crashes that occurred through July 2024.Waymo had completed 25 million driverless miles by July 2024. And by the end of November 2024, Waymo had faced only two potentially successful claims for bodily injury. Both claims are pending, which means they could still be resolved in Waymos favor.One of them was this crash that I described at the beginning of mySeptember articleabout Waymos safety record:On a Friday evening last November, police chased a silver sedan across the San Francisco Bay Bridge. The fleeing vehicle entered San Francisco and went careening through the citys crowded streets. At the intersection of 11th and Folsom streets, it sideswiped the fronts of two other vehicles, veered onto a sidewalk, and hit two pedestrians.According to a local news story, both pedestrians were taken to the hospital, with one suffering major injuries. The driver of the silver sedan was injured, as was a passenger in one of the other vehicles. No one was injured in the third car, a driverless Waymo robotaxi.It seems unlikely that an insurance adjuster will ultimately hold Waymo responsible for these injuries.The other pending injury claim doesnt seem like a slam dunk, either. In that case, another vehicle steered into a bike lane before crashing into a Waymo as it was making a left turn.But lets assume that both crashes are judged to be Waymos fault. That would still be a strong overall safety record.Based on insurance industry records, Waymo and Swiss Re estimate that human drivers in San Francisco and Phoenix would generate about 26 successful bodily injury claims over 25 million miles of driving. So even if both of the pending claims against Waymo succeed, two injuries represent a more than 90 percent reduction in successful injury claims relative to typical human drivers.The reduction in property damage claims is almost as dramatic. Waymos vehicles generated nine successful or pending property damage claims over its first 25 million miles. Waymo and Swiss Re estimate that human drivers in the same geographic areas would have generated 78 property damage claims. So Waymo generated 88 percent fewer property damage claims than typical human drivers.Timothy B. Lee was on staff at Ars Technica from 2017 to 2021. Today he writes Understanding AI, a newsletter that explores how AI works and how it's changing our world. You can subscribe here.Timothy B. LeeSenior tech policy reporterTimothy B. LeeSenior tech policy reporter Timothy is a senior reporter covering tech policy and the future of transportation. He lives in Washington DC. 59 Comments
