Enlarge / A Waymo self-driving car in downtown San Francisco on Bush and Sansome Streets as it drives and transports passengers. (credit: JasonDoiy | iStock Unreleased)

Crashing into parked cars, drifting over into oncoming traffic, intruding into construction zones—all this "unexpected behavior" from Waymo's self-driving vehicles may be violating traffic laws, the US National Highway Traffic Safety Administration (NHTSA) said Monday.

To better understand Waymo's potential safety risks, NHTSA's Office of Defects Investigation (ODI) is now looking into 22 incident reports involving cars equipped with Waymo’s fifth-generation automated driving system. Seventeen incidents involved collisions, but none involved injuries.

Some of the reports came directly from Waymo, while others "were identified based on publicly available reports," NHTSA said. The reports document single-party crashes into "stationary and semi-stationary objects such as gates and chains" as well as instances in which Waymo cars "appeared to disobey traffic safety control devices."