The Future of Functional Parking Design
Ever wondered what goes into designing multi-story parking? Parking is an essential component of the built environment in our modern world, yet it is a convenience that most end users don’t give much consideration. Few may know but beyond the aisles, ramps and painted lines there is a wealth of scientific research and engineering that goes into parkade design.
Many readers have experienced the evolution of the parking lot: surface parking has given way to multi-story solutions which in turn has also evolved beyond the older utilitarian styles, giving way to more aesthetically pleasing structures. This is because owners and developers have realized that parking accommodations represent the first and last impressions that users experience when visiting their properties, and that parking functionality is a key factor in determining user satisfaction, translating into higher usage rates and better returns.
Example of a Modern Parking Facility
Precast has become the structural system of choice for most parking garages, mainly due to undisputed advantages such as:
- Superior durability
- Shorter construction program
- Long, open spans for higher layout flexibility
- High quality architectural finishes
However, the functional design characteristics are really what define how well a parking garage serves its purpose. PCI MNL 129-15 gives these specific considerations as:
Level of Service
Self-park vs. attendant/valet park considers whether the vehicle will be parked and retrieved by the owner/operator or by an attendant. Self-park is the most common type of operation, but attended facilities optimize the use of space due to stacked parking layouts. See Level of Service (LOS) discussion below.
IBC building occupancy classification requirements for mechanical ventilation, fire suppression, fire rating, means of egress, and may impose limitations on number of floors, area of each floor and more. Garages can be considered either open or enclosed based on the internal free space and external openings. Introducing mixed use classifications will also affect the functional design in this aspect.
Access control systems and cashier booths are normally placed at the entrances and exits of the parking lot to manage and facilitate access and payment based on the privileges of the user.
Street Access Design
The inter-relationship between the entrances and exits of a parking garage and the external traffic flow are critical design considerations. Usually, it is advantageous to have multiple entrances to the garage depending on peak traffic flow entering the garage. Other factors such as signage, relationship to intersections, queuing lanes and location of the access control point are also key factors. Exits on the other hand should be placed on low-volume streets to reduce delays due to congestion when exiting. Multiple exit lanes should be deployed if peak volumes are high.
Minimum clearance according to IBC is 7’-0” for typical parking, whereas ADA requires a minimum of 8’-2” in areas accessible by vans (and can be as much as 9’-6” in other areas). Typical structural floor depth is in the range of 3’-0” to 3’-6”. Therefore, floor heights are generally in the 10’-0” to 12’-0” range.
Circulation and Ramping
The circulation and ramping design is one of the most complex components of functional parking design. This considers the type of facility, peak flows, flow direction, topography and relationship to entrances, exits, adjacent facilities and streets. There are many types of circulation and ramp systems with pros and cons which affect the end user depending on the type of facility.
Examples of Circulation and Ramp Systems
Parking configuration is important in that it directly affects the parking efficiency and construction costs. Parking configuration is classified by Level of Service (LOS), which is the relationship between parking-space angle and width, drive-aisle width, number and radii of turns, ceiling heights, lighting levels, ramp slopes, pedestrian crossings, entry/exit location and design, revenue control systems, vehicle travel distances, and the traffic circulation system; all of which are functional design elements affecting the end user. There are 4 LOS criteria from A to D:
LOS A = Excellent LOS B = Good LOS C = Average LOS D = Tolerable
Generally, users with lower familiarity and higher turnover (eg shopping malls and hospitals) should be granted LOS A or B. Higher familiarity, lower turnover (eg commuter, employee, resident parking) can tolerate a lower level of service.
LOS ties in with the parking angle, stall module and aisle widths and interlock reduction (projection of the parking stall as a result of the parking angle less than 90 degrees). Higher LOS have wider module widths, stall widths and aisle width and are easier to navigate.
ADA mandates compliance with accessibility guidelines for disabled users, governing factors such as:
- Number of accessible parking spaces
- Minimum sizes for accessible spaces
- Types of accessible routes (slopes, ramps etc)
- Accessibility standards for the facility (offices, washrooms etc)
Safety and Security
Owners and operators have a duty of care to the patrons to ensure their safety and security. Specialized firms and consultants are often employed to assess the risks and design safety and security features. Features range from lighting and overall visibility to guard patrols and monitored CCTV.
Wayfinding, Signage and Graphics
Overall navigation of the facility relay heavily on the functional design of the wayfinding, signage and graphical elements. It is both a science and an art which relies on visual cues and if not deployed effectively, will result in confusion for the end user, inhibiting their ability to reach their destination. This is true for both vehicular and pedestrian traffic in the facility.
All of these functional aspects of design are described in great detail in PCI MNL 129-15. As such, readers are encouraged to learn more, and can access the manual for free here:
Precast Prestressed Concrete Parking Structures:Recommended Practice for Design and Construction
However, Functional design may change drastically very soon
With the advent of self-driving vehicles and automated parking, patrons may no longer need to interact with parking structures in the same way. What this means is that many of the functional design parameters may be affected drastically or become irrelevant, changing the overall design of parking facilities altogether.
Consider this example:
Or This one:
Both of these examples have the possibility to affect or negate many or all of the functional design parameters currently used in parking garage design because the user no longer accesses the parking facility in the same way. Parking facilities of this type, although potentially much more efficient on space will no doubt be more expensive for the owner/operator and for the user, both due to the capital expense of the automated systems and the convenience factor for the user.
Until automated parking becomes more common, some car companies are investing heavily in the development of self-driving and/or self-parking vehicles. This also has the potential to shake things up in the functional design of parking facilities as is may allow for re-definition of the level-of-service approach somewhat as autonomous vehicles become more common. Angled parking spaces and stall size may become less of a consideration, for example, leading to more efficient facility design.
See an example here: Audi Q7 (2018) Automated Parking
Do you have any insights to share regarding parking facility design?
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