Extra parking means extra pollution, one authority says

Can an overabundance of parking spaces cause more air pollution than what would typically be generated had that extra parking provision not been there in the first place? Yes, says one authority.

On the TransForm blog, Ann Cheng in “Too much parking is a waste of money and space: Lessons from Seattle,” explains, “Too much parking is … a well-documented contributor to increased automobile ownership, congestion, and pollution.”

But how?

Cheng goes on to state, “Particularly in transit-rich neighborhoods, new housing can lead to a reduction in public transportation ridership if new homes attract residents who are used to driving, and enable them to keep doing so. Parking oversupply can silently undermine our best intentions for cleaner air, safer streets, and affordable homes – but it can be difficult to avoid, especially when zoning codes and city ordinances require more parking than is actually needed.”

And how can one calculate the right parking for a given development project? This is where something called the Right Size Parking Calculator (Calculator) comes in.

Developed by King County (Washington) Metro Transit, according to Cheng, the Calculator is a tool used to assist municipalities determine the correct number of parking spaces for, say, a housing project, based on location and building attributes.

Lead staffer for King County Metro Transit’s Right Size Parking program is Daniel Rowe who “calculates that for a typical suburban multifamily project with 150 homes, roughly $800,000 is spent to build parking spaces that will sit vacant,” wrote Cheng. “That increases the average cost of living in one of those homes by over $5,000 – whether through increased rent, fees, and/or purchase price.” The idea of Right Size Parking is to help developers and municipalities establish the correct parking-supply-versus-parking-demand balance.

To this, Cheng adds: “With projections calling for over 400,000 new homes in the next 25 years to accommodate population growth in the [San Francisco] Bay Area, extra unused parking could cost a fortune. At a conservative estimate of $20,000 per parking space, the price tag for an average oversupply similar to King County’s would be upward of $3.2 billion.”

That money could instead be used for improvements to other aspects of transportation, the kind that result in greater mobility and improved energy efficiency and air quality.

Conversely, more parking, like more road building, encourages more automobile purchases and more driving, apparently, and more driving results in higher emissions releases, the assumption here, of course, being the source of propulsion power for the vehicles in question is the internal combustion engine.

More suburban sprawl means more parking and more pollution, a cause-and-effect that need not be.

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