Car manufacturer Tesla's announcement that one of its customers has died in an accident while using their car's Autopilot feature marks a sad step in the development of driverless cars.
Tesla confirmed that the fatal accident occurred when the car's Autopilot system was engaged on a highway, and the car subsequently hit a tractor trailer that was crossing the road.
The company was quick to point out the technology's safety record, saying that this was "the first known fatality in just over 130 million miles where Autopilot was activated".
But the loss will raise concerns about the safety of driverless cars and technologies.
It will also act as an important first test for an industry that must overcome some significant consumer scepticism about the need for autonomous vehicles.
What are the safety concerns around driverless cars?
After this accident, one of the most pressing challenges for the driverless car industry will be to persuade consumers that its vehicles are safe.
Previous surveys of people's attitudes have shown that, for many consumers, trust in the safety of driverless cars is still a big concern.
For example, one survey found that almost half of UK consumers would be unwilling to travel as a passenger in a driverless car, while four in ten would not trust an autonomous car to drive safely.
Age is also a factor – another survey revealed that almost two-fifths of vehicle owners born before 1964 would not trust self-driving technology, compared to just 11% of owners born between 1995 and 2000.
From now on, whenever questions are raised about the safety of driverless vehicles, critics may point to this incident as proof of why autonomous technologies should not yet be trusted.
But supporters of driverless cars – and those who recognise that even a fatal incident such as this one is unlikely to derail the industry's longer-term development – will stress the need to view such accidents in the context of some of the wider benefits offered by driverless cars, such as lower congestion, safer streets and improved mobility.
Accident data from driverless vehicles can also be used to improve safety, according to Sahar Danesh, Principal Policy Advisor for Transport at the Institution of Engineering and Technology.
"One of the advantages autonomous vehicles have over traditional vehicles is that they record everything that goes on around them in detail, so those investigating what happened in the case of the self-driven Tesla will have a lot of information that they can use to improve the future safety of autonomous transport," said Danesh.
The accident can also be viewed against the backdrop of a high level of road fatalities involving human drivers. Statistically, nearly 100 people die every day in motor vehicle traffic deaths in the U.S. alone – a figure that appears to have increased in 2015, according to the U.S. National Highway Traffic Safety Administration (NHTSA).
The safety debate will doubtless continue as more incidents take place and evidence emerges both for and against autonomous technologies. But the driverless car industry now faces a significant reputational challenge as it deals with the aftermath of the first fatality involving one of its vehicles.
How has Tesla responded?
Tesla has stressed that its Autopilot technology is still officially in a public beta phase, and that drivers must maintain control and responsibility for their vehicles at all times.
"As more real-world miles accumulate and the software logic accounts for increasingly rare events, the probability of injury will keep decreasing," said Tesla. "Autopilot is getting better all the time, but it is not perfect and still requires the driver to remain alert.
"Nonetheless, when used in conjunction with driver oversight, the data is unequivocal that Autopilot reduces driver workload and results in a statistically significant improvement in safety when compared to purely manual driving", the company noted.
According to Tesla, the NHTSA is investigating the crash, and will explore "whether the system worked according to expectations".
As the NHTSA begins its investigation, one thing is almost certain. This is unlikely to be the last fatality involving driverless technologies.
For Tesla and other driverless car manufacturers, the safety aspect will therefore continue to be critical if the industry is to persuade drivers to hand over control to self-driving cars.
What is Tesla's Autopilot feature?
The company describes its Autopilot feature as a technology that helps its Model S cars to 'steer within a lane, change lanes with the simple tap of a turn signal, and manage speed by using active, traffic-aware cruise control. Digital control of motors, brakes, and steering helps avoid collisions from the front and sides, and prevents the car from wandering off the road.'
In an approach similar to that taken by many vehicle manufacturers, Tesla has opted for technology that is not yet completely autonomous. Its Autopilot system assists motorists with certain driving tasks, but doesn't take over from them completely. This contrasts with the approach being taken by companies such as Google, whose self-driving car project aims to deliver a completely driverless vehicle.
The software that powers Tesla's technology can be updated over the air, meaning that as soon as the company makes improvements to its code, all of its Model S drivers stand to benefit.
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