Wednesday, February 15, 2012

The Environmental Impact of Parking Spaces and Structures

Parking Infrastructure and the Environment (Mikhail Chester, Arpad Horvath, and Samer Madanat, ACCESS, Fall 2011)

Also discussed here: Paved, but Still Alive (Michael Kimmelman, New York Times, Jan. 6, 2012)

The article reviewed today looks at the overall economic and environmental life-cycle costs, both direct and indirect, for the provision of parking facilities and associated costs associated with travel to the parking spaces and the road infrastructure. The overall cost for the USA is between $4 and 20 Billion, depending on which of 4 scenarios are assumed for the number of spaces per vehicle. The environment impacts in terms of greenhouse gas emissions or health hazardous pollutants (SO2, PM10) are also significant as shown in the figure below.



“Figure 1 shows total emissions caused directly and indirectly by automobiles if all the LCA emissions from parking are attributed to automobiles.”

Key Quotes:

“vehicles spend most of their lives parked. Because abundant free parking encourages solo driving and thus discourages walking, biking, and the use of public transit, it greatly contributes to urban congestion”

“Past LCAs[life-cycle assessments]..have focused on evaluating the resources directly used for travel and have not considered the extensive parking infrastructure, including the costs of its construction, operation, maintenance, and raw material extraction and processing”

“Evaluating life-cycle effects, including health care and environmental damage costs, we determine that emissions from parking infrastructure cost the US between $4 and $20 billion annually, or between $6 and $23 per space per year”

“There are roughly 240 million passenger vehicles and 10 million on-road freight vehicles in the US. All passenger vehicles require a home base and commuting vehicles also require a work space. In addition, using data from a nationwide inventory, we reach a figure of 105 million metered spaces”

Scenarios:
  • "A includes the number of parking spaces at commercial sites.. 722 million spaces
  • B, we evaluate roadway design guidelines and distances of urban and rural roadways to determine nationwide on-street parking…810 million spaces.
  • C is based on observed ratios of four spaces per vehicle for cities and 2.2 spaces per vehicle for rural areas…844 million spaces.
  • D is based on an unverified estimate of 8 spaces per vehicle that is often mentioned in planning literature…2 billion spaces”
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