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Green Parking

Parking designers and planners are joining the ever-growing legion of individuals concerned with climate change, and its effects on natural habitats and species. Looking to make their own “green” gestures, designers and planners are implementing sustainable, environmental-friendly elements and features into parking structures and surface parking lots.

Designers and planners are discovering that “green” design elements are not only good for ensuring a parking surface lot or parking structure’s sustainability efforts, but good for the bottom line, saving tens of thousands of dollars each year. When applied properly, “green” parking design elements can also help protect area water supplies and visually enhance a site.

Detailed below are some of the more popular “green” design elements being applied in parking structures and surface parking lots across the country.

Porous Pavement and Stone Reservoirs
Most surface parking lots are made of pavement, an impervious material that collects stormwater on its surface and does not allow it to filter into the soil. Surface parking lots have traditionally been built with pipes, curbing, gutters and drains to channel stormwater. However, the stormwater is often contaminated with many types of petroleum residues, fertilizers, pesticides and other pollutants from parking surfaces. The water also enters a municipality’s sewer system at an unnaturally high rate and volume. According to the United States Geological Survey, an impervious, man-made surface will generate two to six times more runo? than a natural surface.

A system that includes porous pavement and stone reservoirs is one way to fix this problem. Under such a system, rainwater passes through the porous pavement and collects in a reservoir located underneath the surface. The rainwater is treated for the containments that frequently accumulate in parking lots before being directed toward a municipality’s sewer system. The temperature of the water is reduced; the rainwater is also released at decreased volumes and at a much slower rate than in a typical drainage infrastructure system, guaranteeing the municipality’s sewer system is not overwhelmed.

‘Green’ Landscape Elements

There are also a number of landscape elements that can “green” up a surface parking lot. For example, rain gardens collect rainwater runoff, and help lower nitrogen and phosphorus levels. They typically consist of a grass bu?er strip, a shallow ponding area, an organic layer, planting soil and vegetation. Rain gardens are typically used in parking lot islands and are ideal for surface parking lots in dense urban areas with few open spaces.

Bio-swales, which are vegetated storm water collection areas that slope to a destination, are another way to reduce the negative impacts of surface lots. Bio-swales are open channels or depressions with dense vegetation used to transport, decelerate and treat runo?. At surface parking lots, they are designed to help direct water into bioretention areas. Unlike rain gardens, they require a large amount of surface space and are better suited for more rural areas.

Parking designers and planners are also implementing design features such as: dry retention basins, which are designed to detain runoff for a short amount of time, helping to limit flooding and other stormwater impacts; wet retention basins, which have the capacity to store a permanent pool of water and are efficient in terms of water control; and infiltration systems, which are designed to allow runoff to gradually infiltrate into the ground over a period of hours or days.

“Green” surface lots can also feature large canopy trees to provide maximum shade. This cools pavement surfaces, creates a more pleasant environment and helps reduce heat island effect, a phenomenon that causes metropolitan areas to be significantly warmer than surrounding rural areas.

Other Design Elements to Consider

Surface lots are typically constructed of black asphalt, which absorbs the heat of the sun and contributes to heat island effect. A number of permeable and semi­permeable substitutions can be used to reduce such an effect, including gravel, pervious concrete, wood mulch, turf blocks and natural stone. Also, when constructed with an infiltration system, alternative pavers can function similarly to porous paving systems.

Other design elements to consider include the size of a surface lot. Unfortunately, many surface lot designs call for more spaces than actually necessary, as it’s a common practice to set parking ratios to accommodate the highest hourly parking during peak seasons. By determining average parking demand, a lower maximum number of parking spaces can be set to accommodate vehicles, which would save parking administrators money.

Designers and planners should also consider the size of parking spaces. Many lots feature unnecessarily large space dimensions, which only contributes to the overall size of a surface lot, thus making its ecological footprint more significant.

‘Green’ Parking Structures

Parking planners and designers are also incorporating “green” design elements in parking structures. This includes using materials such as precast, recycled concrete or concrete containing recovered materials. Also, concrete areas are being cured with low volatile organic compounds (VOC) and covered with low-VOC paints. VOCs are emitted as gases from certain solids or liquids, and may have short- and long-term adverse health effects.

“Green” parking structures are also featuring strategies and technology aimed at reducing the number of idling automobiles in a garage. When vehicles sit waiting to enter or leave a parking structure, they unnecessarily emit carbon monoxide. Reversible lanes are used to reduce the number of idling vehicles in a garage and the pollution they emit. Reversible lanes can be used as entrances during peak entry times and then changed over to exits during common departure times. As for technology solutions, pay-on-foot kiosks allow patrons to pay for parking before they get into their cars to leave, which shortens the long lines leaving a structure, minimizing the amount of time patrons spend waiting in running vehicles.

A Strong Commitment

As today’s designers and planners have seen, the “green” revolution has reached the parking industry, and the positive economic and environmental impacts are being felt throughout. Even the smallest “green”-influenced changes show the industry is strongly committed to taking responsibility for protecting the environment for future generations.

David Rich is director of business development for Rich and Associates. Based in Southfield, Mich., Rich and Associates is the oldest firm in North America dedicated solely to parking design and planning. David Rich can be reached at