A consumer advocacy group in the United States says Tesla needs to fix flaws in its Autopilot driver-assistance system following a fatal crash in California, Reuters reports.

The National Transportation Safety Board (NTSB) recently concluded that the driver of a 2017 Model X, Walter Huang, had Autopilot activated when the vehicle smashed into a crash attenuator and concrete barrier.

The system had provided the 38-year old with two visual alerts and one auditory alert that he must place his hands on the steering wheel. However, the last of these alerts came 15 minutes before the crash. Huang’s hands were not on the wheel in the six seconds before the impact.

Moreover, the NTSB found out that the vehicle had sped up from 62 mph (100 km/h) to 71 mph (114 km/h) in the final three seconds.

In response, director of Cars and Product Policy and Analysis for Consumers Union, David Friedman, said Tesla needs to address underlying problems with the system.

“[The NTSB’s] alarming report reinforces why Tesla must respond immediately to previous concerns raised about its driver-assist system.

“[The crash] demonstrates that Tesla’s system can’t dependably navigate common road situations on its own, and fails to keep the driver engaged exactly when it is needed most.”

Huang’s family lawyer, Mark Fong, asserts “there was a failure of both the Tesla Autopilot and the automatic braking systems of the car.”