Maintaining road infrastructure will be a key factor during the ‘transitional stage’ of autonomous vehicles, according to a new report.
The paper, published by EuroRAP in partnership with the Road Safety Foundation and iRAP, examines the relationship between road infrastructure and safety for conventional and increasingly-autonomous vehicles (AVs) as the latter become more common on road networks.
The report says new risks are likely to arise where road maintenance is poor – because worn out road markings are easily missed by AV detection technology – which ‘could lead to crashes’.
The report adds that as potential driver liability decreases, the liability of road authorities and vehicle manufacturers looks set to rise – meaning road maintenance will become a ‘higher-priority obligation’.
In terms of road infrastructure, the report argues that some countermeasures which are currently popular because of the protection they provide to car occupants, such as roundabouts, may become less necessary.
Other countermeasures for crashes involving conventional vehicles, but also benefiting other road-users – such as street lighting and anti-skid surfacing – may become more difficult to justify economically unless they also assist AVs.
The report also examines example crash scenarios and how they might be affected when half of all travel is by autonomous vehicles.
The report concludes that some of the greatest crash risks for conventional vehicles – such as run-off, head-on, intersection and shunt crashes – are likely to reduce with the introduction of AVs; as a result of the impact of lane-keeping technology, enhanced road positioning, speed management, vehicle to vehicle connectivity and autonomous emergency braking.
The number of rear-end shunt and run-off crashes is expected to reduce by 60-80%, while head-on crashes are expected to fall by 40-60%. Crashes involving vulnerable road users and at intersections could fall by between 20-40%.
Dr Steve Lawson, EuroRAP regional director and report author, said: “Increasing automation currently relies on clear road line markings and signs that can be reliably detected, and road users need to be able to anticipate AV manoeuvres accurately for safe, smooth traffic flow.
“Roads that cars can consistently and unequivocally read will be key to safety in the changeover period as the common factor of reliance for both driver-operated and automated vehicles.”
Ferry Smith, EuroRAP chairman, said: “Increasing vehicle safety will make a significant contribution but the transition to universal use of autonomous vehicles will, at best, take decades.
“What we do know is that in the transition to AVs, and probably beyond that period, roads that cars can read – through good and consistent signing and lining – will be essential, as AVs at various stages of transition, and drivers of vehicles without an autonomous function, continue to rely on them.
“The shift to AVs should be prepared and planned for now, but should not be a distraction from the life-saving work that can be done using conventional approaches to crash reduction.”