Parking simulation: a new approach to parking design

We now have the modelling tools to predict and visualise how a car park will operate before it is built. Doing this at an early stage of the design process allows asset owners to easily test multiple parking layouts and mitigation measures, and ensures the final design works before committing to large capital investments, says Francesco Zhou

Francesco Zhou

Francesco Zhou

Figure 1: Comparison of Statistics between Different Parking Layouts and Management Systems

Figure 1: Comparison of Statistics between Different Parking Layouts and Management Systems

Figure 4: Modelling Large Multi-Storey Car Parks

Figure 4: Modelling Large Multi-Storey Car Parks

Figure 2: Modelling Different Parking Configurations

Figure 2: Modelling Different Parking Configurations

Figure 3: Visualising Impacts of Ticket Gates

Figure 3: Visualising Impacts of Ticket Gates

How often do we see car parks being built, and not meeting the end users’ needs? Time and again we reach our destination, be it a mall on a Friday or an office during the week, and we are faced with the dreaded experience of circling around a car park looking for a space, or being stuck in a queue waiting to even enter the car park. 

Whilst sometimes this may be down to a shortage of parking spaces, often these issues arise due to poor car park design and signage. So what is wrong with the way we design car parks? Conventionally, car parks are designed based on a set of design guidelines and standards, and assessed using some basic ‘first principles’ analysis. 

Although this approach ensures that car parks meet the relevant design requirements and parking demand, we often overlook how the car park will actually operate during the design stage. How is the parking utilisation distributed across different areas and levels of the car park? How do vehicles looking for parking or maneuvering in and out of spaces affect the internal circulation? What are the impacts of queues on ingress and egress times? How effective are mitigation measures at resolving these queues? All of these are questions that often remain unanswered until the car park becomes operational. 

This can result in the operational issues we see every day in car parks in the UAE, and worldwide. As end users, this translates into lost time and frustration. As asset owners, this means additional costs due to design and construction rework or loss in number of customers.  

Informed decisions

Over 40 years ago, we moved from a strictly theoretical design approach to roads, to more advanced traffic modelling methods. This has enabled us to produce effective road designs more efficiently, and make better informed decisions during the design stages. In the same way we changed our perspective of road design, there is now a need to revolutionise the way we approach parking design. 

Today, we have the modelling tools to predict and visualise how a car park will operate before it is built. Doing this at an early stage of the design process allows asset owners to easily test multiple parking layouts and mitigation measures, and ensure the final design works before committing to large capital investments.   

Parking simulation is a planning tool that uses modelling software to replicate driving and parking behaviours based on a set of parameters and assumptions. When assessing the circulation within car parks, we often overlook the fact that each individual will have different behaviours and preferences: parking as close as possible to their destination, and would rather circle around the car park until they find a parking space that is close enough, while others prefer to avoid having to search for a parking space. Unlike traditional parking analysis tools, parking simulation considers individual vehicle behaviours and preferences, and dictates each vehicle’s decision and movement, based on these behaviours and preferences. 

Predicting the circulation within a car park is certainly useful, as it will identify the need for any mitigation measures. Asset owners however, are not interested in if they need mitigation measures, but rather what mitigation measures they need to make their car park work. To this end, the true strength of parking simulation is its ability to predict how the circulation inside a car park will change in response to changes in layout or the introduction of traffic management measures.

Take our previous example on parking preferences. Most of us (particularly in the Middle East), prefer to park as close as possible to our final destination, which can often lead to queues and congestion due to the inefficient circulation of vehicles inside the car park. These issues can be alleviated by implementing systems such as Variable Message Signs (VMS), but what are the impacts on average search times and queue lengths? Using parking simulation we can now quantify the impacts of these mitigation measures and assess whether it is worth implementing them. 

Other useful applications include modelling different parking configurations, access barriers and ticketing strategies. These applications can be modelled for all types of parking environments, from multi-storey car parks to on-street parking, from taxi ranks to freight and logistic sites.

The analytical capability, along with the visual outputs and videos that can be produced from these models, make parking simulation an extremely powerful tool, particularly when it comes to stakeholder engagement. The opportunity to actually visualise how the car park will operate before constructing it, offers our clients reassurance that the proposed design will work. This often results in expedited project delivery and approval processes.

Of course, no model can forecast with 100 per cent accuracy how a car park will operate in the future, and models will only be as robust as the assumptions they are based on. The concept can sometimes be misleading for clients who may interpret positive modelling results as a guarantee that the design will work. This level of uncertainty can be mitigated by undertaking sensitivity tests and validating the model assumptions with observed data. 

The additional cost to undertake parking simulation modelling compared to traditional parking assessments is another factor that may discourage clients from using the tool, particularly as parking simulation is currently not a requirement for authority approvals. Whilst parking simulation does come at an additional cost during the design process, this cost is potentially minimal compared to the rework cost incurred to redesign or rebuild the car park after it is operational. If the success of a scheme starts at the planning stage, simulation is certainly one of the ways to get it right. 

New software

Currently, there are several parking simulation software on the market such as Citilabs Dynasim and PTV Vissim. Both are established micro-simulation software that model parking as well as highway and urban road networks. Vissim is used for traffic micro-simulation within the Middle East and although it specialises predominantly in highway and roads simulation, it offers some features for modelling off-street and on-street parking. Dynasim on the other hand specialises specifically in parking simulation, and offers the added capability of modelling large, complex car parks, as well as replicating in greater detail parking behaviours. 

Whilst parking simulation is currently a niche market sector in the Middle East, it is undoubtedly a market that is set to grow, along with the choices of available software.

As we face parking issues on a daily basis, it is clear that there is a need to change our approach to parking design and planning. Consultancies and authorities have started to realise this and are gradually changing their way of designing car parks by using increasingly more advanced modelling tools. We are ready for the change, are you?

Francesco Zhou works in AECOM’s Dubai office