By John Sharp

Automated vehicles (AVs) have become a key feature on urban roads in the US and China, and after extensive trials, they are now here in the UK. A new landmark in the advance of AVs was seen on 3 September, when the first of a fleet of 15 driverless taxis was launched in London – albeit with a human ‘driver’ in the front seat – and it’s a matter of when, rather than if, AVs will become a widespread presence on our roads.

What remains unclear, however, is what impact this will have on the transport sector’s sustainability goals. Richard Dilks, chief executive of Collaborative Mobility UK (CoMoUK), the national organisation for shared transport, recently co-authored the white paper Driverless Shouldn’t Be Directionless. Published in July this year, the document makes it clear that “self-driving vehicles can absolutely make our roads safer and significantly cut carbon emissions.”

However, Dilks stresses that government policy is critical. “I don’t see how we are going to get to net zero if we don’t shape emerging things such as AVs,” he says. “They are the latest emerging force in transport that needs our attention.”

The right balance

The potential benefits to sustainability that AVs offer have been identified in numerous studies. A reduction in the need for drivers to own their own vehicles may bring congestion and emissions down, while models have been suggested to promote driving efficiency, guiding cars through intersections at the right times to minimise emission-related acceleration and deceleration. Other possibilities include ‘platooning’, where vehicles travel closer together to reduce air drag and fuel consumption.

Research by Dr Limor Nahmias-Biran and colleagues at Tel-Aviv University found that AVs offered benefits such as first- and last-mile transport options in less car-dependent cities such as London, as well as better mobility and travel opportunities for more disadvantaged groups. Meanwhile, in more car-dependent areas where transport networks are more disparate, such as the US and Canada, AVs could provide a cost-effective alternative to public transit or private car travel while bridging accessibility gaps for those without a private vehicle.

Affordability, however, is bound to come into play, with the possibility that AVs will become a first class mode of travel. “We need to consider the impacts AVs have on journey quality and times for more affordable transport.” says Dilks. “Will we end up in a world where buses are getting slower and slower as the rich people zip about in their AVs?”

Work, rest and play

Another potential issue could be ‘induced demand’, where, if personal AVs became commonplace, people might tolerate longer commutes in the knowledge that they could sleep or work in their cars, increasing the amount of traffic on the streets. Here’s where local authorities would need legislation in place to potentially restrict AV traffic, and Dilks suggests more positive policies might also encourage sustainable AV use.

The CoMoUK report suggests that AVs could be integrated into public transport hubs, with ‘robotaxi’ trips being utilised by multiple people. “This would not just be a taxi service for a couple of miles at either end of a train or bus journey,” explains Dilks, “but car clubs for travellers going further, for longer.”

Dilks believes that more clarity will be needed from government in terms of how AVs can benefit communities and contribute significantly to sustainability. “All the UK has done so far is to move relatively fast on enabling robotaxi trials to happen rather than going into what these things actually should be for,” he says, “That debate needs to happen soon to really maximise their potential.”

• Read CIHT’s response to the DfT’s consultation on the future safety of automated vehicles here.

• Book your place for the online CIHT Masterclass on sustainable transport on September 17 here.