The hype around connected autonomous vehicles (CAVs) remains at fever pitch.

Any article on them is usually accompanied by hyperbole such as revolution, transformation etc. There seems to be a puppy-like excitement in central government and other quarters that CAVs are going to come along and solve all our transport problems. They’re going to make the roads safer, they’re going to magic away congestion and they’re going to enable everyone, regardless of age or ability to drive, to have unfettered mobility.

“Model shows that only 2,000 private cars needed in Barcelona if 500 shared shuttles also deployed” cries one headline. The Lisbon Study undertaken by PTV showed that Lisbon could cut the number of cars by 90% and car parking by 94%, if CAVs were fully deployed, figures that were veraciously lapped up by the headline writers. However, if you read the small print, PTV are very careful to lay out a range of assumptions they’d made for the modelling exercise: that the CAVs would offer shared rides, they would pick up from corner to corner with a wait time of between 0-10 minutes and for trips heading downtown, they would take you to a mass transit hub to transfer you on to high capacity public transport. So we seem to be selling the benefits of astronomic reductions in numbers of vehicles which rely on CAVs being deployed as shared rides and connecting to mass transit, whilst allowing people to assume that CAVs will provide door to door private mobility.

I’ve spent most of my professional life trying to persuade people to abandon the private car – just for the occasional trip. And it’s hard. Trying to get people to surrender their private car completely seems likely to be very challenging. Jillian Anable’s classic psychographic segmentation work segmented the population by attitudes towards mobility.  Half of the population was made up of “die hard drivers” (think Top Gear fans), “car complacents” (don’t see any need to change), and “car aspirers”(can’t wait to get a car).  Are they going to want to surrender the steering wheel, let alone the car?

The technical work being undertaken on CAVs, from robotics and navigation through to systems management epitomises human ingenuity. But how much of this ingenuity is being focused on the more prosaic issues of how will we interact with them, how will our travel behaviour be affected by them and what impact they will have on the cities in which we live?

So I have 10 questions or challenges.

  1. Are people willing to share autonomous vehicles? The claimed benefits for CAVs rely on them being shared. Of course there are two types of sharing. The first type of sharing is where the vehicle is shared but rides are private. Are people going to be willing to give up their own private car? As Anable’s research showed, a large number of people love their cars. At the other end of the spectrum, lots of people, particularly families, transport a huge amount of clobber with them on journeys and I struggle to envisage how a car that turns up on demand could fit that lifestyle. Second, there is sharing the journey. Are people going to jump into a CAV and share a ride with strangers? Some research by the MERGE project in Greenwich suggests not. Albeit a small survey, a minority of people were willing to share a CAV ride with strangers: “In addition to the potential social discomfort of sharing a car with strangers, a number of …respondents thought that it would feel ‘frighteningly isolated’ without an authority figure present”. Hmm, so we need a larger vehicle that’s capable of holding many passengers with some sort of transport official present. Can we think of some sort of new Brilliant Urban Solution (“Bus”) for that?  
  2. Who’s going to make sure that CAVs are used as shared vehicles? Who’s going to stop people taking ‘private’ AVs down town rather than travelling to the transport hub to catch mass transit. It’s doubtful that government will legislate to enforce shared use. Are local authorities going to regulate that city centre zones are shared CAVs only? Even now, as many local authorities face pressing air quality issues, lots of clear air zones proposals only apply to buses, taxis and HGVs – it seems that addressing private individuals’ car use is politically too difficult.


    So I just don’t buy the idea that CAVs are going to be deployed and used in a predominantly shared manner.

    And what will CAVs do to levels of travel and use of other modes?

  3. We have an inactivity crisis in this country and we’re (supposed to be) trying to get more people walking and cycling. Won’t the ability to jump into an autonomous vehicle undermine our attempts to get people walking and cycling?
  4. Whilst a real benefit of AVs could be the ability for people who can’t drive (for reasons of age, choice or impairment) to be able to access facilities, could this create a whole new tranche of additional travel? “The emergence of AVs should enable new waves of untapped mobility demand from young people and seniors” pronounces a KPMG report. Instead of walking my 5 year old to the local school, shall I stick her in a CAV to travel to the school across town that did slightly better in the league tables? Will I decide to live out in my rural idyll and commute long distance back into town? It doesn’t really matter how bad the congestion is, because I can get work done on the journey.


    So how is any of this going to solve congestion?

    And what about the design and use of our cities’ streets and public spaces?

  5. When you see visionary images of the city of tomorrow with its CAV fleet, it typically shows a nice wide boulevard with a bus lane, bike lane, and perhaps even an avenue of trees separating pedestrians from the traffic. Unfortunately, as we know too well, many of our medieval town planners didn’t plan their streets very well for the car, let alone for CAVs. So on narrow streets where a sub-standard width footway is directly next to the carriageway, how will CAVs operate along here? What happens when I step out into the carriageway to manoeuvre past another pedestrian? There has been some speculation that competition amongst shared driverless cars could incrementally eek away at safety. Whether this is likely or not, I’m unsure, but are unintended consequences being thought through?
  6. Will there, sooner or later, be pressure brought by lobbies to ban behaviours such as crossing the street away from a pedestrian crossing, or cycling on a street without cycle infrastructure? Will our transformation and revolution simply be a return to the bad old days of the 1960s when we tried to make roads safer for pedestrians and cyclists by forcing them off the road?
  7. Will the market for CAVs focus on the big cities and the wealthiest, most mobile groups? Will they reach suburban areas and rural areas (where the need and the potential benefits are greater)? Will this worsen mobility inequality? 


    And finally onto some commercial stuff:
  8. Who’s going to pay for the transformation of our city streets and infrastructure to make them ‘CAV compliant’? Are the manufacturers going to provide this investment, or will it fall to the eternally cash-strapped public sector, just as the requirement to strengthen bridges and roads to accommodate ever larger and heavier trucks did? You can imagine the pressure to transform your city to make it CAV compliant so as to keep up with other cities, and the consequent diversion of funding from walking, cycling, public transport and public realm investment to support this.
  9. And with shared use, electric vehicles radically reducing VED and fuel tax revenues, how are we going to address the financial black hole? Road-pricing would be the obvious solution, so why isn’t a public conversation about road pricing happening in parallel to discussing CAVs.
  10. Are commercial car manufacturers going to prefer to sell a fleet of 10 shared autonomous vehicles or a fleet of 100 private AVs? How invested in shared are they? Could they be just spinning this wonderful feel-good future vision to establish the ground conditions to sell more units? Cynical I know. You’d never see a car advert selling a mythical lifestyle where someone is driving round a city devoid of other traffic would you? Or a car manufacturer fabricating their emissions standards to keep sales up.

I’m sure some people have got answers to some of these questions, and these issues are being looked into, but it does seem that the effort examining the technology aspects is far outweighing considerations of the human angle in this. I do like NACTO’s “Blueprint for autonomous urbanism” which sought to lay out how autonomous vehicles should be deployed in the city and illustrated street designs to accommodate them effectively, but I haven’t seen a huge amount more than this. 


As a former town planning student, the whole discussion around autonomous vehicles has unerring parallels to the enthusiasm for modernist planning in the 1950s/1960s. Advocates enthusiastically told us how this brave new modernist world was going to transform the urban space and solve congestion.  60 years on and not many of us are fans of what was accomplished. If you have time, have a look at this wonderful ‘Mr Chomondley-Warner style’ video showing Edinburgh's 1950s plans to knock down “a clutter of ancient shops and dwellings” to replace them with a “beautiful” new organised shopping centre. Any similarities between this and the rose-tinted views about how CAVs will benefit us in the future?

P.S. they’re knocking down that shopping centre in Edinburgh now, whilst quite a lot of the clutter of ancient buildings remains…..