NBC News reports a case of how at 4am an autonomously-driven Cruise vehicle stopped at a red light when it was rear-ended by a Honda. The Honda driver reversed backward several feet, stopped and drove forward again, making contact with the Cruise vehicle a second time.

The Honda driver then left the scene without exchanging information with the two injured test drivers.

NBC claims it is part of a pattern bedevilling tech companies that are trying to make driverless cars a reality.  Last year there were 32 cases where a person driving a car or truck left the scene of a crash involving their vehicle and an autonomous vehicle. The problem has continued at a similar pace this year, with seven examples as of early March.

Anderson Franco, a personal injury attorney said that those crashing into self driving cars think they can get away with it.

"If you are operating your own vehicle and you crash into an autonomous vehicle, the correct thing to do is take photographs, call the police and have it documented," he said.

But it sometimes needs to be clarified from the outside of a Cruise or other autonomous vehicle what to do if there's a problem. Cruise said in a statement to NBC News that it was making its phone number more prominently displayed on the outside of vehicles so drivers in a crash know who to call..

Autonomous vehicles are usually equipped with various external cameras that could record the license plate numbers of hit-and-run drivers. Still, it’s not clear how often the companies have gone down that road as the hit-and-runs are usually minor.

It said it works with San Francisco police "when necessary" and searches its videos for the license plate numbers of other cars "if needed." Cruise declined to comment on specific cases. Waymo said it has kept its options open about how to respond to hit-and-runs.