Spotting a fire truck ahead is easy for people, but not so for self-driving cars

The sensors on a Tesla and other cars are relatively good at following a vehicle in the same lane and adjusting speed to maintain a safe distance. But when a vehicle changes lanes — known as the “cut-out scenario” — it can leave the trailing vehicle’s sensors struggling to assess what’s ahead.

“The cut-out is one of the hardest scenarios,” said Phil Koopman, an engineering professor at Carnegie Mellon University and co-founder of Edge Case Research, a Pittsburgh-based autonomous vehicle technology company. “There’s no question about that.”

The radar and camera system on the Tesla involved in the Jan. 22, 2018, crash in Culver City, California, didn’t “see” the fire truck in time to brake, according to the NTSB. The car’s automatic braking system didn’t activate, though it gave the driver a collision warning 0.49 seconds before impact, the investigation found.