NTSB determines immediate cause of fatal Uber crash was failure of human operator

Following an 18-month investigation, the National Transportation Safety Board (NTSB) has released its conclusions on the fatal collision between an Uber-owned autonomous vehicle and a pedestrian in Arizona last year. As reported in our previous blog post, Arizona prosecutors determined that Uber was not criminally liable for the crash. Now, NTSB has concluded that "[h]ad the vehicle operator been attentive, she would likely have had sufficient time to detect and react to the crossing pedestrian to avoid the crash or mitigate the impact".

The NTSB report also calls on the National Highway Traffic Safety Administration (NHTSA) to require mandatory safety self-assessment reports before autonomous vehicles can take to the roads.

The collision

The collision occurred just before 10pm on 18 March 2018 when a modified Volvo XC90 operating in autonomous mode struck Elaine Herzberg as she walked her bicycle across a road in Tempe, Arizona. The autonomous vehicle, which had a backup driver behind the wheel, detected Ms Herzberg almost six seconds before impact, but failed to correctly classify her as a pedestrian or predict her path. The car's emergency breaking system had been disabled at the time of the collision and instead relied on the operator's intervention.

Video from the vehicle's inward-facing camera showed that the operator was looking away from the road in the lead up to the crash, and looked up only one second before impact. According to police reports, the operator had been streaming a television show on her phone. The operator began steering left just 0.02 seconds before impact, and struck Ms Herzberg at a speed of 39 mph. Ms Herzberg later died as a result of her injuries.

NTSB's findings

NTSB has determined that the immediate cause of the collision was the failure of the operator to closely monitor the road and the operation of the automated driving system. NTSB noted that the operator's "prolonged visual distraction, a typical effect of automation complacency, led to her failure to detect the pedestrian in time to avoid the collision".

The report goes on to say that Uber did not adequately recognise the risk of automation complacency and develop effective countermeasures to control the risk of operator disengagement. In particular, NTSB criticised inadequate safety risk assessment procedures and a lack of oversight of vehicle operators, including not making use of the ability to retroactively monitor the behaviour of vehicle operators and their adherence to operational procedures. The report further states that these deficiencies were exacerbated by the decision to remove the second vehicle operator during testing.

The report calls on NHTSA (as well as the state of Arizona and the American Association of Motor Vehicle Administrators) to take a more active role in relation to regulating autonomous vehicles. The existing national framework relies on NHTSA's guidelines for autonomous vehicles, and involves only a voluntary self-assessment process. There are no mandatory federal safety standards relating specifically to autonomous vehicles. NTSB therefore recommends that NHTSA should:

1. require entities who are testing or who intend to test a development automated driving system on public roads to submit a safety self-assessment report; and
2. establish a process for the ongoing evaluation of such safety self-assessment reports and determine whether the plans include appropriate safeguards, including adequate monitoring of vehicle operator engagement.

NTSB's findings have been published in summary form, with the full report expected to be released within the next few weeks.

Changes to come?

The regulation of autonomous vehicles is receiving an increasing amount of public interest, and concern. NTSB's findings were released the day before a US Senate hearing on autonomous vehicles. At the hearing, transportation officials noted that in the absence of a comprehensive federal safety framework, state regulation is leading to the creation of a patchwork of laws, which can harm economic growth, create confusion and ultimately negatively affect safety.

In light of NTSB's findings and increasing interest in the development of a federal regulatory framework, it will remain important for manufactures to monitor regulatory developments. In addition, autonomous vehicle manufacturers can learn from NTSB's criticisms in this case, and should be mindful to adequately address safety concerns in the development and testing of autonomous vehicles.