The impact of autonomous vehicles on urban planning

Self-driving vehicles (Connected Autonomous Vehicles or CAVs), along with electrification and sharing, will revolutionise how people travel by road in the future. In this paper, Associate Director Luke Kendall examines how the design of urban areas will need to respond to the introduction of CAVs, and with some urgency.

The current situation

Automation already exists in a limited form in public and private transport, from driver-assisted cars to automated systems such as the Dockland Light Rail system in London. CAVs, however, are a step change.

In recent years in the UK, we have started to see a shift away from private car ownership, although there are regional differences. This has in part seen an increased move to public transport but more significantly micro-mobility such as cycling and scootering, a trend that is set to continue as people prioritise their health and the environment. Click here to read more about the cycling boom.

We also know that electric vehicle (eVs) adoption in the UK is gradually accelerating. 66% more eVs were registered in 2020 than in 2019, and in September 2021 eVs made up 23.1% of new car registrations[i]. What is detracting from wider adoption is that cost in the UK of electric vehicles is around 1.3 x that of a conventional car while in other some European countries it is on a par. In the UK there are fewer charging points, and of these only 3% are ultra-fast change points, compared with 12% in Germany and 25% in China[ii]. You can find out more about street charging by reading our related article here.

What are the benefits of Autonomous Vehicles?

• An AV trip can be shared - Driverless cars could collect people from around the same locality or be shared between employees.
• Reduced cost - The removal of the cost of a driver from driverless taxi/Uber-type services.
• Reduced number of vehicles - Several studies suggest that the introduction of CAVs could lead to as much as a 90% reduction in vehicle need. There are likely to be fewer, but harder working, vehicles on the road, leading to decreased congestion and increased road space.
• Increased access for individuals with disabilities, older people and children - A larger part of the population will be able to take part in daily mobility.
• People will be willing to take longer trips - People will be less reliant on living close to their places of work or education. They can use their journey time more effectively for work, reading, or even just family time.
• Increased safety - CAVs will, in theory, be better driven leading to reduced road incidents. ‘Mobility corridors’ can be created to be shared with pedestrians and cyclists. A mobility corridor is where different modes of transport are brought closer together to share a common route without the need for separation in levels and design. Read our paper about rebalancing the streets for more on this, including an emerging Dutch model.

What will be the impact on urban planning?

“Planners think in 30-year increments, and autonomous vehicles are already hitting the streets today. Urban planners should be terrified.”[iii] Nico Larco, co-director of the Sustainable Cities Initiative.

Our urban environments have suffered from too many cars chasing too little space.

A host of measures have been introduced to discourage or restrict the use of the private car, including regulation (such as congestion charging) and physically and financially prioritising alternative modes of transport.

We can assume that we will need to devote less space to CAVs for driving, parking and manoeuvring. This will allow us to use more of the public realm for other uses, say, soft landscaping. Urban grids can therefore be narrower, allowing for more intimate spaces, and shaded through the proximity of adjoining buildings.

Drop off and pick up zones.

With AVs will come the desire to be dropped off at the door rather than finding a parking space and walking to the destination. Ad hoc drop-offs (like how a taxi operates now), can add to congestion if sensible locations are not provided. So, while some space may be reclaimed, some may still be required. We may see subterranean car parks retained as pickup and drop-off locations as well as being repurposed to accommodate the increase in other modes of micro-mobility.

CAVs would need fewer parking facilities as they would not need to sit idle. They could carry out trips for others or tasks such as click and collect pickups.

Current studies[iv] suggest that we could see as much as a 70% reduction in parking demand in towns and cities. This will require a significant rethinking of our development requirements and regulations and will shift land value.

What about commercial vehicles?

Most studies focus on the impact on private cars and public transport. But there will also be consequences for commercial vehicles. If we can assume for a moment that delivery vehicles will not require an operative (a person) for loading and unloading, then cost will be reduced. Even if we assume someone is required for loading, the removal of the driver potentially increases safety. Deliveries could be better scheduled outside busy hours at more unsociable times and completed with more accuracy.

The logistics sector is already starting to introduce AVs for mail, parcel and even food deliveries. It is hoped the eVTOLs (electric devices with Virtual Take-off and Landing) for people and goods will further ease ground-level congestion, although ground-level deliveries are with us for the foreseeable future.

Platooning, or driving close together in a group, is something that has so far generally been considered for truck movements outside urban areas. It is possible that the principle could be applied to some areas of our urban network as individual vehicles start to aggregate together.

How Chapman Taylor is responding to the challenge

AVs will be adopted, and CAVs, or at least voiceless with this ability, will be adopted in parallel. The recent acceleration of change suggests adoption is likely to be quicker than anticipated - more like a 10-year window. As designers, we are therefore going to be increasingly asked to consider the accommodation of CAVs.

In the short to medium term, we are considering the challenge of how to repurpose parking structures, particularly when they are integral to a property. We have already been considering this due to the reduction in private cars accessing town centres. We are exploring repurposing, rather than redeveloping, as this is a more sustainable way of retaining a high embodied carbon structure. Uses we have considered to date include workplace, residential, retail, play and recreational spaces, leisure and hydro or aeroponic farming.

The need for less parking space and the potential for more space-sharing, such as in ‘mobility corridors’, may reinvigorate the design of our public realm as we move away from the dominance of the private internal combustion car.

Adoption of CAVs is likely to be contained or frustrated by the ability and flexibility of our streets to accommodate them during a period of transition. At Chapman Taylor we are planning for this now.

[i] DfT - Department for Transportation (UK)

[ii] The Economist; https://impact.economist.com/s...

[iii] https://www.archpaper.com/2017/12/how-autonomous-vehicles-change-way-architects-planners-think/

[iv] https://www.archdaily.com/931640/how-will-autonomous-vehicles-impact-cities