Waymo is recalling nearly 3,900 robotaxis after their self-driving software repeatedly failed to recognize ramp closures and construction zones in incidents in Arizona and California, according to a recall notice posted by the National Highway Traffic Safety Administration. 

The recall comes after Waymo reviewed incidents that occurred in April and May in Phoenix and the San Francisco Bay Area. The autonomous driving company temporarily restricted the robotaxis from driving on the freeway while it investigated the issue.

The recall impacts Waymo's so-called 5th Generation Automated Driving System (ADS), which powers its fleet of Jaguar vehicles. The NHTSA said all of the recalled vehicles are believed to have the software defect.

"Under certain circumstances, the [autonomous vehicle] may enter and drive at speed in freeway construction zones due to inappropriately prioritizing the avoidance of other freeway hazards and/or failing to recognize the construction zone," the recall notice states.

Waymo, a subsidiary of Alphabet, expanded freeway driving last year, adding the capability to its vehicles in San Francisco, Phoenix and Los Angeles. 

The incidents included six in Phoenix, where Waymo robotaxis failed to recognize ramp-closure signs and drove into freeway construction zones. In May, another seven Waymo vehicles entered freeway lanes with active construction in the San Francisco area, driving between cones marking closures in adjacent lanes, according to the notice.

"Driving at speed in a freeway construction zone increases the potential for collisions," NHTSA said.

In one May incident, Elliot Slade told CBS San Francisco that he and his fiancée were in a Waymo vehicle traveling from San Mateo, California, to their San Francisco home when the car sped through a construction zone and was chased by police.

"The Waymo started freaking out as we got closer to the merge cause the lanes were kind of all merging," Slade said. "One lane was gone, another lane was, who knows where it was. Cars were all over the place going in."

Slade said he worried that they wouldn't survive the trip. 

"There were construction signs," he added. "There were lights going on. Police in the distance, and it sped up. That's when I looked at my fiancée, we're done. This is it. We're dead. We're going to die right here in the Waymo."

The robotaxi eventually veered from the highway into a residential neighborhood. Slade said Waymo gave him three free rides, each worth up to $40, but he wasn't sure he would use them.