The second vehicle has a more pronounced damage to the engine compartment.
Police spokesman Seth Tyler said it is believed that this is the first Waymo collision in Chandler this year. Dash-cam video from Uber's fatal accident in March-when one of its cars in autonomous mode struck and killed Elaine Hertzberg-showed that that event was probably avoidable, contrary to initial police statements.
A Waymo self-driving vehicle was involved in a serious accident in Chandler, Arizona earlier this afternoon.
A Waymo vehicle in autonomous mode was struck by another driver during what appeared to be a head-on collision in Chandler.
Tyler said that an eastbound vehicle swerved in the intersection to avoid a northbound auto, traveling into the westbound lanes, where the driver struck the Waymo minivan.
Twitter user Matt Jaffee posted a photo of the accident scene at 3:40 p.m. PT. Jaffee tweeted: "Right now: Pretty gnarly crash with an @Waymo van in Chandler, AZ".
Waymo is a self-driving auto initiative from Google's parent company Alphabet. The Waymo self-driving vehicle was said to be travelling at a low speed which minimised the impact of the crash.
The incident-two months after an Uber self-driving auto struck and killed a pedestrian in nearby Tempe-is still under investigation, but early indications are that it was not the fault of the autonomous vehicle. A Waymo employee would be in the vehicle, but in the back seat.
"We are concerned about the well-being and safety of our test driver and wish her a full recovery", Waymo said. TNC status means Waymo can charge riders for service.