What’s the true cost of parking?

In 2014, Sarah Goodyear wrote a piece for CityLab titled "How Parking Spaces are Eating Our Cities Alive" that provides a framework for answering the question. In her article, Goodyear discusses how the average parking space takes up about 300 square feet, or “the size of a studio apartment in New York,” according to the article. That wasted space is compounded across the average city, Goodyear argues, creating vast areas that are not only heavily dependent on cars, but that also contain lots of empty parking spaces much of the time.

This begs the question: exactly how many 300-square-foot parking spaces are being left vacant?  It's alarming to reflect on the amount of unused real estate that’s being taken up by parking, especially when we consider how these spaces happen to correspond in size to a much-needed housing type. If these unused parking spots were converted to apartments, would the cost of housing fall? 
 
In Boston, a study by the Metropolitan Area Planning Council explains that this is, in fact, the case. Andy Metzger of CommonWealth writes about the issue, stating, "Over the course of three years, the council determined that during the peak-demand period–overnight on weeknights in the fall, winter, and spring–only about 70-percent of parking supplied by residential developments was being used."

"Looking at the available off-street parking facilities at 189 developments with a total of 19,600 units, the council counted nearly 6,000 empty spaces, totaling more than 41 acres of pavement. The construction cost of those unused spaces totals an estimated $94.5 million, representing about $5,000 per housing unit in the survey."

According to the report, local land-use regulations should implement requirements that appropriately align land-use with the actual demand for these spaces. The oversupplying of parking, the report states, has become a major urban issue. Metzger adds, "The study recommends that the cost of car parking be unbundled from the cost of housing. The council assigned blame for the over-supply to blanket municipal regulations that don't comport to the needs on the ground."

Although these numbers are specific to Boston, the data directly links the cost of housing in the larger metropolitan area with the city's horrific traffic and congestion issues, perhaps providing much needed insight for other dense cities like, Los Angeles, New York, and Washington, D.C., with similar problems.