Waymo recalls 3,900 robotaxis over construction zone software flawWaymo is recalling 3,871 robotaxis after a software flaw caused vehicles to enter closed freeway construction zones, the National Highway Traffic Safety Administration disclosed Wednesday.According to NHTSA, the fifth-generation automated driving system at the heart of the recall could, in some situations, speed into active freeway construction zones — either because it failed to detect closure signs or because it gave too much weight to steering clear of other hazards on the road. The fix will include software improvements as well as additional operational protocols, the agency said."We identified an area of improvement regarding performance around freeway construction zones," Waymo said in a statement. "We voluntarily restricted freeway operations last month while making improvements, proactively notified state and federal regulators, and decided to file a voluntary software recall with NHTSA."AdvertisementAdvertisementPhoenix was the site of the earliest triggering incidents: a single episode on April 11 and then a cluster of five more on April 19, all involving vehicles that failed to respond correctly to construction zone closures. In response, Waymo's field safety committee pulled back on freeway operations as engineers worked to address the underlying problem. A subsequent incident on May 18 involved seven vehicles in the San Francisco Bay Area that bypassed traffic cones and wound up traveling through lanes where construction was actively underway. A review of further data on how vehicles behaved near construction zones led Waymo's safety board, on June 8, to authorize a formal recall, according to Reuters.This is the second recall Waymo has filed in just over a month. That earlier action, in May, saw the company pull back roughly 3,800 robotaxis over a software vulnerability that left vehicles unable to avoid flooded roadways where speed limits were elevated. The May recall traced back to April 20, when extreme weather in San Antonio sent a driverless Waymo car into a submerged lane; because no passengers were aboard, the incident caused no injuries.Waymo has faced a series of regulatory actions over the past two years. A separate NHTSA inquiry is ongoing after a Waymo vehicle collided with a child in January outside a Santa Monica, California elementary school, leaving the child with minor injuries. The National Transportation Safety Board has opened its own probe into cases where Waymo cars passed stopped school buses that had their warning lights activated, a violation of state law. A December recall addressed that school bus issue.Waymo has emphasized that filing a voluntary software recall is essentially a commitment to deploy a fix — not an order to ground the fleet.