Autonomous Vehicles – More Parking

Autonomous Vehicles – More Parking

January 2018


Will Private AV Use have an Influence on Parking?


In recent years a number of commentators have presented an expectation that the future of city centre car parks might be in doubt. Widespread use of AVs would mean that demand for city centre car parks would diminish as AVs were dispatched to the suburbs to locate lower cost parking.

In contrast, in the article by Steer Davies Gleave and KPMG “How will autonomous vehicles change parking?” (Parking Review January 2018) under a scenario where AVs are largely privately owned, they concluded that the impact on parking will be limited.

This article explores these different viewpoints, and sets out why a private model of AV ownership is likely to have some, but certainly much less, impact than we may have at first thought.


Modelling & Observing Impacts


At the 2017 Transport Research Board Annual Meeting there was a presentation of some modelling to attempt to quantify parking choice by AVs. Using only a 5% market penetration of AVs on an existing highway model of Atlanta, Georgia, the authors found that under charged parking scenarios, city centre parking demand reduced by 4½% as vehicles relocated to park in lower cost suburbs (Zhang & Guhathakurta, 2017). The authors noted the implications that this may have for additional vehicle kilometres and that parking charges may need to work in tandem with public policy to reduce unwanted trips.

Further quantification as to the scale of these empty miles were provided by a doctorate paper. Having worked several months as an uber driver, the author had collated the number of miles he travelled with passengers on board and the empty miles spent going to collect those passengers. His analysis was conservative, and certain empty mileage legs were discounted where they were not in direct relationship to the movement of passengers. His conclusion was that over 90% of his miles were empty (Henao, 2017). It is not unrealistic to consider that with the advent of SAVs the issue of empty mileage will be significant.


Policy Response


Without any control on empty mileage many of the advantages of the AV will be rapidly eroded. While indeed it may be fine to carry on doing something else while the vehicle works its way through a congested street, this still does not present the level of efficiency and speed from A to B. There will be many occasions that speed of transfer is still very important.

So while suburban parking may be less expensive, will the costs of getting to it outweigh the benefits? Having dismissed the vehicle to the suburbs, and left it to take an hour to make the two mile trip through highly congested streets, what time should I arrange it to return? If I find that my meeting finishes early I could of course immediately summon the vehicle but would have to wait an hour for it to return. I too would then have to sit through the considerable congestion caused by all the other re-positioning AV trips.

Michael Hurwitz, Transport for London’s Director of Transport Innovation has stated that AVs driving around to avoid parking charges “would not be good for the network” (Local Transport Today, 2017). If the advent of AVs seeking lower cost parking creates huge additional social costs on the rest of society, and those AVs that do have occupants inside are seriously delayed by those that don’t, it will be an obvious step to discourage empty miles using fiscal or legislative measures.

It seems inevitable that congestion charges or other policies will be applied, added to whatever fuel costs are incurred through re-positioning, to remove any competitive advantage from suburban parking over city parking.




The other factor that makes this re-distribution model less likely is the chronology over which things develop. The SDG article refers to timing being important. It will be the order of events, and the availability of options to the market that will likely shape the future choices rather than necessarily the “best” option viewed with the benefit of everyone working towards a common good. It will be the wealthiest that first enjoy the AV. They won’t want to, nor need to, lend it out during the day for others to use as an SAV nor will they tolerate waiting for it to come pick them up when it is time to do so. The vanguard of AV owners will want city centre convenient parking and be in a position to pay for it. This type of usage will set the tone for others to follow. It is quite feasible that, just like the car, the AV will continue to be a personalised statement and private entity for its owner’s convenience that each social strata aspires to own.  

The other chronology aspect is that long before AVs can go looking for lower cost parking on the public highway, they will be allowed to go park themselves within the confines of private space. A city centre multi-storey car park, that is made off-limits to the public, could become a free-drive zone for those AVs that at that stage cannot drive on the public highway without human supervision.

On entry to the car park, the driver would leave the vehicle and control of the AV could be handed over to a master controller within the car park that would use the sensors within the car, as well as all the wall and ceiling mounted sensors within the car park, to guide the vehicle into a parking spot. Already the International Parking Institute is discussing the necessary standards and software protocols to allow this to happen (International Parking Institute, 2017) and trials under the GATEway research programme began in the UK in December to examine automated valet parking (Parking Review, 2018). Without the need to open car doors or have such wide aisle widths there are opportunities to increase occupancy from the same space. Moreover the master control system can drive any vehicle or device within the car park. This means that each parking bay could be double stacked and if appropriate based on the user-type, the aisles could be double parked with short stay users positions in front of those that typically stay all day. Even if the assumption proved wrong, simultaneously re-arranging a number of cars to extract a vehicle that was blocked-in would be possible, and quite rapid, using the master control.


Intensified Use


Research into this intensified use of the city centre car park indicates that the amount of space taken per vehicle could reduce by 60%. (Audi, 2015). This is more than doubling the amount of cars parked in the same structure. These figures are based on new-build; the structure would have no stairs or lifts. With the potential to double occupancy within the city centre parking structure, the price charged could thus be lowered making the incentive to go find parking elsewhere, when that becomes possible and notwithstanding all the difficulties described, less significant.

There is a need however to consider again where we are and what we have rather than an immediate jump to the end-state. Indications are that converting existing structures will generate the intensification benefits identified but not at all to the same extent as those presented for a new build structure in the US. Examination of the additional capacity that could be achieved from existing multi-storey car parks in Norwich and Blackpool indicated the saving was a more modest 8% and 12% respectively (Potter, 2017). Much of the savings gained within the car park were given up providing a suitable reception area on the ground floor. Examination of a car park in Croydon with a difficult configuration produced only 3% increase in occupancy whereas a large structure in Fawley, with stacking, could potentially increase capacity by a further 50% (ibid).

So does this mean that we can look forward to a Darwinian battle of the car parks in our city centres? Those that can evolve to accommodate stackers, smaller parking bays and aisles will no doubt become more competitive in price and take the AV market share. Those car parks that cannot increase occupancy will become less competitive. They may not necessarily become unviable though. As now, those locations that prove to be less suitable for parking and more suitable for something else will in time be re-purposed. It appears that under a private AV model this change is likely to be progressive rather than dramatic.


Re-Purposing by Design


There are some interesting designs and articles emerging showing how multi-storey car parks may be re-purposed, and design changes that will allow them to be converted into offices or homes at some point in the future. It appears however that rather than re-purposing a structure, managing the type, age and distribution of the parking estate across a city centre to allow a progressive reduction in the overall parking footprint by redeveloping specific parking facilities, may prove more pragmatic and cost effective. If the better returns on investment on the automation process needed to intensify parking are more readily achieved in multi-storey car parks, it may be that across an estate it is the multi-storey car parks that are retained for parking while it is the surface parking capacity within city boundaries that is brought forward for other uses. This is after all what many Councils have been doing for decades, as they have re-configured their parking stock in response to over or under supply and other needs for more retail, housing, reduced traffic and an enhanced urban core.   


Growth in 24 hour Demand


The greater efficiencies in storage may themselves facilitate a growth in parking demand. We might see the situation that every person has their own AV. Why drive the children to school when they can take their own AV? And the increased occupancies we report above are based on the current vehicle retaining four wheels and being designed for four or five occupants. If a new wave of personalised AVs were to be created that were, literally, personal, and half the size of a current car, we could see the costs of storage, even in city centres, become an acceptable and largely assumed cost of ownership. Moreover would the revenue from a city centre parking facility be not so much dominated by the daytime demand as that earnt overnight? Could a market with an excess of potentially lower cost parking, coupled with the user’s ability to summon vehicles a short distance to their front door, transform car ownership for city centre residents? Freed from the daily challenge of trying to locate parking outside their terraced homes or within neighbouring streets, and no longer constrained to one or two permits for the whole household, AV ownership using nearby off street parking within the urban core may become an attractive option, even if car use remained limited to the weekly shop or weekend away. So far from proving the death of the city centre car park, widespread ownership of one or more smaller private AVs could generate a market for overnight and long term parking for all those living in and close to the core. And with a facility able to organise vehicles based on likely use, storing an AV that is not expected to be required until the weekend, could be quite efficient.




This article has looked at parking largely from a situation where the private AV ownership model dominates. Under that model, the risk to car park owners arising from a mass exodus to park in suburban streets to avoid city centre parking charges appears limited. Both because of the potential intensification within parking structures and the expected charges that will apply to AVs causing congestion through empty miles it appears that suburban parking will not offer equivalence in convenience nor sufficient advantage in cost.

Within the city centre parking stock the AV is likely to reduce the floorspace required. There may be increased demand, both through a wider range of users owning AVs and through the widespread ownership of AVs by those in urban areas currently constrained with somewhere to park that is convenient and affordable. A progressive need to reduce some parking supply will most likely manifest itself through a process of redeveloping parking sites for other uses and a reduced provision in new developments rather than any significant need to re-purpose parking facilities or drastically curtail existing supply.


Andrew Potter

Parking Perspectives




Audi. (2015, November 17). Memorandum of understanding between Audi and US City of Sommerville – Audi brings automated parking to the Boston area. Retrieved from Audi Urban Future initiative:

Henao, A. (2017). Impacts of Ridesourcing on VMT, Parking Demand, Mode Choice and Travel Behaviour P17-21556. Washington DC: Transport Research Board.

International Parking Institute. (2017). IPI DATA EXCHANGE STANDARD (IPI-DATAEX). Retrieved from IPI:

Local Transport Today. (2017, November LTT735 23). New Mobility sevices mist support mayor’s agenda – TfL. Local Transport Todau, pp. 4-5.

Parking Review. (2018, January 309). Public Test out automated valet parking. Parking Review, p. 28.

Potter, M. (2017). Will the Multi-Storey Car Park of 2017 become the AV hub of the future (2030)? Parking & Property 2017. London: unpublished.

WSP Parsons Brinckerhoff Farrells. (2016). Making Better places:Autonomus Vehicles and future opportunities. London: WSP.

Zhang, W., & Guhathakurta, S. (2017). Parking Spaces in the Age of Shared Autonomous Vehicles: How Much Parking Will We Need and Where? Transport Research Board Annual Meeting (pp. 17-05399). Washington DC: TRB.