Parking Facilities: Design

"Parking Facilities: Design" focuses on the physical design attributes and improvements that municipalities should consider in the development of parking facilities.

How it Works

This etool focuses on the physical design attributes and improvements that municipalities should consider in the development of parking facilities. The 'Parking Facilities: Planning' tool focuses on how a municipality may use and/or regulate parking facilities through various parking management planning options to achieve a functionally and environmentally appropriate amount of parking spaces, as well as the use and potential development of park and ride facilities to mitigate traffic congestion.

Vehicular parking facilities play an important role in the efficiency of Chester County's overall transportation system. Parking availability can affect not only the destination, but also the means people will use to reach a destination. The more difficult it is to find available parking; the less likely people will drive their automobiles to a destination. Lack of available parking also makes it more likely that people will utilize public transit if it is available and relatively convenient. If there is a consistent abundance of available parking, it may indicate the parking lot is too large, creating unnecessary environmental impacts such as increased stormwater runoff and heat island effect.

Determining the proper size, location, and layout of parking facilities are important decisions that municipalities must make to provide the most appropriate level of parking within a community. Facility types generally include off-street surface parking, on-street parking, and structured parking (parking garages).

Parking and landscaping at Eagleview Town Center

Benefits

Safety

Safer pedestrian conditions can be encouraged by minimizing vehicular conflicts and providing adequate lighting.

Energy Efficiency

The provision of properly designed and adequate parking facilities can encourage more public transit use and reduce the heat island effect that can lower cooling costs for adjacent structures.

Environmental Quality

Properly designed parking facilities can improve water quality by filtering and cooling stormwater runoff through stormwater best management practices, including vegetated swales and rain gardens.

Aesthetics

Good parking design can mitigate the visual impacts of surface parking lots with landscape material and/or visual buffers.

Get Started

Parking facility design must reflect many factors, including the amount of space available for the facility, the number of parking spaces required by the destination's land use, environmental and site-specific conditions. The following provides general design principles and guidance regarding the physical elements to be addressed when developing parking facilities.

Site Work

Basic design principles to consider when deciding where parking facilities should be located include:

• Locate parking areas convenient to building entrances;
• Minimize extensive grading operations by designing with the topography;
• Slope parking areas between a minimum of 1% and a maximum of 5%, with an ideal slope of 2%;
• Create multiple smaller parking areas rather than one large mass;
• Integrate planted islands to increase aesthetics and improve runoff collection opportunities;
• Use topography and trees to mitigate negative visual impacts;
• Minimize negative impacts on the natural environment such as the unnecessary removal of mature vegetation or compromising soil stability; and,
• Utilize rectangular parking area configurations to minimize land area requirements.

Pedestrian Circulation

The orientation and configuration of parking spaces must be considered early in the development process to create a safe and convenient facility:

• Circulation systems should be designed to minimize the number of conflicts between vehicular, bicycle, and pedestrian traffic;
• Pedestrian circulation should always have a higher priority than vehicular circulation;
• Rows of parking spaces should be aligned perpendicular to the facility it serves to minimize the number of pedestrian crossings of driveway aisles;
• Interconnected sidewalk systems should exist in and around the parking lot;
• Sidewalks should connect to all building entrances;
• A landscaped sidewalk should be provided in larger parking lots;
• Crosswalks should be provided, along with speed tables where appropriate; and,
• Sidewalks should connect to abutting streets.

Safe Vehicle Circulation

• All off-street parking facilities should be accessible without backing into or otherwise re-entering a public right-of-way;
• Customer and employee parking areas should be separated when applicable to allow for better turnover nearest the main facility entrance;
• Turning radii should be provided to accommodate the largest vehicles that will utilize the facility, such as refuse haulers, buses, and tractor trailers;
• Parking rows should be located on each side of a driveway aisle for paving efficiency; and,
• Dead end parking areas should be avoided whenever possible.

Off-street Parking

Off-street parking is the most common type of parking facility. These facilities have traditionally been developed as one large parking area resulting in expanses of asphalt with little consideration for the negative visual impacts or stormwater implications. Parking lot designers should limit the places where pedestrians are forced to cross vehicular traffic, and reduce redundant driveways, inefficient single stacked parking bays, locations where cars need to back into intersections, limit vehicular stops and turning movements, as well as consider appropriate locations for trash enclosure pads with regard for trash vehicle turning radii.

Parking angle configurations

One of the first decisions to make when designing a parking facility is to determine the safest and most efficient configuration of the available space to meet the parking requirements. There are several different parking angle configurations to be considered, including perpendicular (or 90 degree) and other angled (60, 45, 30 degrees) options. The following provides basic descriptions and dimensions including the advantages and disadvantages for each configuration type:

Perpendicular (90 degree)

This is the most efficient and economical parking configuration because it accommodates the most vehicles per square foot of available parking area. Perpendicular configurations work best with two-directional driveway aisles; one way drive aisle configurations have almost the same space requirements and offer little advantage in circulation. Standard dimensions for this configuration are 9 foot wide by 18-foot-deep spaces with a 24-foot wide (two-directional) driveway aisle for a total 60-foot-wide cross section.

Advantages

• Handles the most vehicles per square foot of available space
• Handles most vehicles per linear foot along a driveway

Disadvantages

• Requires the widest dimension (60 ft) for a double bay
• Difficult maneuvering for some drivers compared to other angled options

Angled-60 Degree

The primary advantage with any angled parking is the ability to provide more spaces or better circulation patterns when the space available for parking is dimensionally constrained. The 60-degree angled parking configuration is ideal for a fast turnover rate or predominantly short-term use and may be preferred over 90-degree parking in some situations due to ease of navigation, even though it may be a less efficient use of the available space. Standard dimensions for this configuration are 9 foot wide by 20-foot-deep spaces with a 24-foot wide (two-directional) driveway aisle for a total 64-foot-wide cross section, or 16-foot wide (one-directional) driveway aisle for a total 56-foot-wide cross section.

Advantages

• Easy maneuvering in and out of parking spaces due to better visibility
• Lends itself to either one-or two-way aisles
• Works best with short term and high turnover situations

Disadvantages

• Requires more pavement per vehicle than perpendicular configurations
• Handles fewer vehicles per linear foot

Angled-30 Degree

Similar to 45-degree configurations, this configuration progressively increases the amount of pavement required per space while narrowing the double bay cross section. Standard dimensions for this configuration are 9 foot wide by 16.5-foot-deep spaces with a 12-foot wide (one-directional) driveway aisle for a total 45-foot-wide cross section.

Advantages

• Easiest spaces to back out from a visibility standpoint
• Least required width for double bay cross section

Disadvantages

• Requires the most pavement per vehicle parking space
• Does not work well with two-way aisle

Landscaping

The most attractive and arguably the most functional and sustainable parking areas are those that are well landscaped. Trees provide valuable additions to parking areas, whether planted in curbed islands or located on the parking area perimeters. Trees provide shade, visually reduce the mass of open pavement, help absorb and filter stormwater runoff, block light and dust, and mitigate heat. The following are some general considerations for how plant materials can be used to improve parking facilities:

• Provide internal parking islands to break up large expanses of paving and reduce the heat island effect;
• Provide appropriately scaled, well-graded and planted earthen berms or mounds, decorative fences, or walls around parking area perimeters to screen the parking area from streets and other facilities; and,
• Minimize the use of medium to tall shrubs on internal curbed parking islands to allow for greater visibility within a parking area
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Other factors to consider in the planting design for a parking facility include:

• Parking areas are not conducive to healthy plant growth due to reflected sunlight, heat gain, and exhaust fumes. Only plant species that are tolerant of these extreme conditions should be used.
• Planted islands or strips should be located at the end of all parking rows, every 15 spaces in a row, and every 4 rows of parking.
• Non-porous pavement limits the oxygen and water exchange between plant roots and the atmosphere. Soil compaction resulting from construction amplifies these conditions for existing trees. Consider the use of porous pavements and existing tree protections during construction of these facilities to promote plant health.
• Curbing should be used for planted islands where appropriate to protect against trunk damage created by vehicles.
• In addition to providing curbing and/or bumper blocks, ensure that parking spaces provide sufficient separation from trees and shrubs to avoid damage.
• Native plant species should be selected whenever possible.
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Avoid the following with respect to tree plantings:

• trees with messy fruits or berries;
• brittle-limbed species;
• large leafed deciduous trees that can clog drains and make walking hazardous; and,
• trees susceptible to insects and diseases.
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Trees that should be selected include those that:

• cast medium to dense shade in summer;
• have normal life spans over 60 years;
• thrive in pollution and in the heat of a typical urban environment;
• demonstrate salt and deicing compound tolerance;
• require little pruning and are structurally sound; and,
• are resistant to insects and diseases.
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Lighting

Lighting is an important component of parking lot safety, especially for a facility that has early morning, late afternoon, or nighttime use. The Illuminating Engineering Society (IES) recommended minimum average illumination level for a surface parking lot is 0.5 footcandles. The IES also recommends that all pedestrian routes and entrances/exits should be well lit with a minimum average of 1.0 footcandles. Lighting poles are typically 20-25 feet in height and should be located in islands or in parking perimeters and protected from potential vehicular damage.

Other lighting factors to consider include:

• Lights should be pointed downward to minimize light pollution and excess glare. Cutoff fixtures should be used to avoid light spilling onto neighboring properties.
• Bulb selection will affect the color of light projected. High pressure sodium bulbs are relatively inexpensive yet cast an orange hue while more expensive metal halide bulbs cast more of a white light.
• LED fixtures are now becoming more widely used as the technology for these fixtures has advanced to provide much brighter fixtures. The energy required to power LED fixtures is considerably less than standard bulbs resulting in significant cost savings.

ADA Accessibility

The Americans with Disabilities Act (ADA) Accessibility Guidelines for Buildings and Facilities requires a minimum number of accessible parking spaces be provided based on the total number of spaces included:

Source: ADA Accessibility Guidelines for Buildings and Facilities

Accessible parking spaces serving a specific facility should be located closest to an accessible entrance. If facilities have multiple accessible entrances, accessible parking spaces should be dispersed and located closest to the accessible entrances.

Accessible parking spaces should be at least 8 feet (96 inches) wide. Parking access aisles should be part of an accessible route to the facility entrance. Two accessible parking spaces may share a common access aisle at least 5 feet wide, with the potential for the aisle to be 8 feet minimum width if shared with accessible van parking. Parked vehicle overhangs should not reduce the clear width of an accessible route. Parking spaces and access aisles should be level with surface slopes not exceeding 1:50 or 2% in all directions.

Stormwater Management

Surface parking lots have traditionally been developed with large expanses of asphalt resulting in a significant increase in stormwater runoff. The stormwater was then collected by a drainage system where runoff from large storm events would be temporarily stored in a retention basin then slowly released through control structures into the natural drainage systems. This general concept has been revised and reflected in Pennsylvania through the State's adopted erosion and sediment control regulations where the focus is to infiltrate or recharge a much larger portion of this runoff into the ground. As part of this shift, the National Pollutant Discharge Elimination System (NPDES) as authorized by the federal Clean Water Act now requires a permit for any earth disturbance exceeding 1 acre, where the threshold was previously 5 acres. These permit applications are reviewed by the local Conservation District as part of the land development process.

To help facilitate these new regulations, the state has published the Pennsylvania Stormwater Best Management Practices Manual. Some examples of Best Management Practices (or BMPs) applicable to surface parking include:

• Pervious Pavement with Infiltration Bed
• Infiltration Basin
• Subsurface Infiltration Bed
• Infiltration Trenches
• Rain Garden/Bioretention Areas
• Vegetated Swales and Filter Strips
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These new regulations create unique opportunities to incorporate many of these BMPs into the design of surface parking. Please refer to the 'Examples' section of this tool to see how BMPs have been incorporated into some recent parking lot developments in Pennsylvania.

On-street Parking

On-street parking is most commonly associated with urban or village landscapes and is often metered as a revenue generator as part of a community's parking management program. On-street parking spaces are typically included in the design of the roadway within which they are located and also referred to as 'parallel' parking. Standard dimensions for on-street parallel parking spaces are 8 feet wide by 22 feet long and placed at least 50 feet from any intersection.

On-street angled parking is less common and often associated with historic or central business districts with lesser traffic volumes where it also serves as a traffic calming effect. These installations require much more space within the road right-of-way than parallel parking but offer the opportunity to create more stalls within the same length.

Structured Parking (Parking Garages)

Parking garages are most commonly associated with densely developed urban centers and represent a significant investment in providing for a parking facility. Municipalities that need to provide structured parking should consider not only the development costs but also the long-term operation and management of such a facility. There are many design factors to consider, including:

• The size and shape of the lot where the structure will be developed.
• Who the primary users of the facility will be.
• Connections to the adjacent street network.
• The architectural style of the structure's facades and how they may relate to existing adjacent structures.
• Avoid standalone garages, and instead integrate parking behind, on top, or below new buildings.
• For parking structures visible from primary streets, incorporate facade treatments and public art to minimize visibility of parked vehicles and enhance visual appeal, or design the garage as a mixed-use building, with storefronts or other business uses on the street level, with the goal of encouraging pedestrian activity and integrating it into the character of the neighborhood.

Rain garden/infiltration at the parking lot for the DCNR Elk Country Visitor Center, Benezette, PA

Gravel (porous) paving parking stalls allow for better infiltration at the DCNR Elk Country Visitor Center, Benzette, PA

Example of vegetated bioswales within parking islands at Riverfront Park, Pottstown, PA

This parking lot is solid paving with no trees, a bad example of parking lot design.

This is a good example of trees and planted islands within a commercial parking lot.

Example of a transit stop centrally located within a commercial development with connecting walkways extending through parking areas, Northampton, PA.

Considerations

Pedestrian/Vehicle Conflicts

Unsafe conditions for pedestrians can be created by unnecessary vehicular conflict points and lack of sufficient lighting.

Increased Heat

Heat can be reflected by exposed asphalt or concrete surfaces not shaded by landscape material.

Increased Runoff

Stormwater runoff that may be heated by contact with pavement, and unfiltered water volume can harm natural drainage patterns and ecosystems.

Poor Aesthetics

Unwelcome visual conditions can be created by open expanses of paving with a lack of proper landscaping and/or buffering.

Examples

Borough of Pottstown

Back-in angled on-street parking has recently been installed in the Borough of Pottstown. This installation on East High Street converted two westbound travel lanes and on-street parallel parking into one westbound lane, one bike lane and back-in angled parking within the same available space. Installed in 2003, this concept "has helped revitalize the downtown by slowing traffic, providing more parking spaces adjacent to stores, encouraging bicycling, and making it easier for pedestrians to cross the street."

Phoenixville Borough

Phoenixville Borough has used its subdivision and land development ordinance to regulate the design of parking facilities with the goals of pedestrian safety, safe vehicular circulation, and stormwater runoff mitigation. Design details outlined in their ordinance include parking setbacks from sidewalks, as well as standards for planting strips in nonresidential lots. Guidance within the ordinance regarding parking garages states that where structured parking is located on the same lot with other uses, it shall be designed as a mixed-use building, with storefronts or other business uses on the street level, to encourage pedestrian activity and reduce visual impacts.

Kennett Township

Kennett Township includes design standards in their subdivision and land development ordinance that require planting strips in parking rows of 10 spaces or more, which must be at least ten feet in width for interior islands. This ordinance also requires that dead-end parking areas shall be designed to provide backup and turnaround areas for the end stalls of the parking area.

Resource Links

• Parking Lot Aesthetics
• Site Design, Parking and Zoning for Shopping Centers
• The Parking Garage: Design and Evolution of a Modern Urban Form
• On-Street Parking Enhancements
• Save Our Land, Save Our Town: Traffic Calming (Back-in Parking)
• Pennsylvania Stormwater Best Management Practices (BMP) Manual
• ADA Accessibility Guidelines
• Chester County Planning Commission's Landscapes Design Series

Related Ordinance Requirements

• Phoenixville Subdivision and Land Development Ordinance
• West Chester Borough Subdivision and Land Development Ordinance
• City of Coatesville Subdivision and Land Development Ordinance
• Kennett Township Subdivision and Land Development Ordinance

Related Tools

• Parking Facilities: Planning
• Transit Oriented Development (TOD)
• Bicycle and Pedestrian Facilities: Design