Waymo has temporarily banned its robotaxis from driving on highways as it works out how to handle construction zones, after several vehicles drove into closed sections of road in Phoenix and San Francisco.

The tech giant identified at least 13 incidents where its autonomous vehicles entered restricted areas, with six occurring in Arizona in April and seven in California a month later. The company has previously issued five recalls for various issues, including driving into flooded roads and illegal maneuvers around school buses.

Waymo’s driving software is currently under scrutiny by the NHTSA over an incident where one of its robotaxis struck a child near a school in January. However, the company claims its vehicles have driven almost 170 million miles autonomously, boasting a 13-fold reduction in serious crashes compared to human drivers.

The recall comes as Waymo prepares for a significant expansion into more than 20 cities this year, including London and Tokyo. The move highlights ongoing challenges in developing autonomous vehicles that can handle unexpected scenarios on the road.