Self-driving cars will pave way for people-friendly streets, says study

Adam Millard-Ball: If decision makers wish to capatalise on the potential of autonomous vehicles to create more liveable, walkable urban places, one approach would be to promote ambiguity in street design through shared-space concepts such as woonerf.

Adam Millard-Ball: If decision makers wish to capatalise on the potential of autonomous vehicles to create more liveable, walkable urban places, one approach would be to promote ambiguity in street design through shared-space concepts such as woonerf.

The widespread use of “risk averse” autonomous vehicles could make roads safer for pedestrians, resulting in people-friendly neighbourhoods, according to a new study from the University of California, Santa Cruz.

Self-driving cars will “slow down and yield” to pedestrians and cyclists, said author Adam Millard-Ball, assistant professor at the university’s environmental studies department.

“Autonomous vehicles could empower cyclists to ‘take the lane’ and ride on streets without dedicated bicycle lanes or other infrastructure,” said Millard-Ball. “Jaywalking could also become more prevalent, and parents may feel more confident in allowing children to play on residential streets.”

Millard-Ball's study uses game theory to suggest that pedestrians and cyclists could exploit the “predictable and safe behaviour” of autonomous cars. 

Under current road conditions the “game of cross-walk chicken” has influenced behaviour between different road users. In most cities the “tiny risk of injury or death” means that pedestrians generally act with caution, allowing traffic to flow smoothly.

But this model of road user behaviour might change as self-driving cars become prevalent, said Millard-Ball. Autonomous vehicles are likely to respond very differently to cars driven by people because “they are fundamentally unable to win the game of chicken”. This new mode of transport is likely to obey the rules of the road far more than human drivers. In the current environment, “the driver might not be concentrating, might not see the pedestrian, or might not believe that the pedestrian would really step out and cross”.

In the future pedestrians will realise there is “almost no risk” in stepping out in front of an autonomous vehicle. “There is considerable evidence that autonomous vehicles drive much more cautiously than the majority of human drivers.” 

In almost all the collisions involving Google self-driving cars, they were hit from behind by drivers who were “surprised” they had stopped for a pedestrian, said Millard-Ball.

The change in road use behaviour will depend on pedestrians being able to recognise autonomous vehicles or there being “sufficiently few human drivers in the mix”, the author concedes.

The study considers three possible scenarios. In the first, pedestrians and cyclists dominate the roads, with autonomous vehicles only able to move slowly in urban neighbourhoods. 

In the second scenario, pedestrian movement is controlled by street design, regulatory changes and enforcement. Fences would be erected between pavements and roads to “corral pedestrian traffic along busy streets, marking a return to the mid 20th century street designs the emphasise segregation of road users”.

A third scenario would see travellers put off using autonomous vehicles because they are too slow. “Some travellers may trade the benefits of autonomous vehicles such as the freedom to engage in other activities during the trip, for the speed advantages of human driving.”

These three scenarios will depend on regulation, taxation or street design changes, and none of them may wholly prevail, Millard-Ball pointed out. The impacts of self-driving cars will be shaped not just by technology but also “the legal, policy and urban planning response”.

“If decision makers wish to capatalise on the potential of autonomous vehicles to create more liveable, walkable urban places, one approach would be to promote ambiguity in street design through shared-space concepts such as woonerf.

“Designs that give pedestrians the confidence – and legal priority – to enter  the roadway become more feasible if many or most vehicles are autonomous.”

Widespread use of self-driving cars would reduce vehicle travel, with a shift way from private car ownership to ‘mobility as a service’, believes Millard-Ball. This might pave the way for parking provision, street design and transit networks to be “revolutionised”.

Autonomous vehicles would not need a parking space close to their destination, meaning that some car parks would no longer be necessary, suggests the author. A further knock-on effect would be a fall in vehicles cruising for parking spaces.

Pedestrians, Autonomous Vehicles, and Cities