When people hypothesize the future of self-driving cars, the possibilities seem promising. But on the other side of that, there are very real dangers to this type of technology that lurks in the shadows and can result in serious injury.

A prime example of these dangers took place this past week at a Mazda test drive in Japan. While the dealership representative was demonstrating the CX-5’s new auto-braking technology, the system failed, shooting the car through a near-by plastic barrier injuring both people on board.

Mazda is investigating the crash, Makoto Watanabe, a spokesman for the Japanese automaker, told Bloomberg. He was unable to confirm whether the CX-5 experienced a braking failure or whether other auto-braking system failures have been reported.