A few minutes in most American city centers will be enough to confirm the impression that even urban areas built long before the automobile have since been redesigned to cater to the car. And one of the most important but overlooked aspects of that – with ramifications for everything from new development to tax revenue – is as essential to automobile traffic as a steering wheel: parking.

In a pair of new studies conducted by an interdisciplinary team of scholars at UConn and the State Smart Transportation Initiative (SSTI), researchers examined the physical changes in six city centers around the U.S. between 1960 and 2010 and their impact on municipal revenues.

Among other findings, the researchers concluded that the common practice of requiring a minimum number of parking spaces to be attached to new development – a requirement in a majority of American cities – can inhibit development, fragment the city, and make traffic worse by suppressing people’s ability to walk, bike, or take transit.

When measuring the amount of space given to parking – both on-street parking and garages – the researchers found that tax revenues for that real estate tend to be much lower than for other types of development. The net effect is that cities forego tax money with every parking spot they require: in Hartford, for example, the researchers calculated that the city forfeits $1,200 per year per parking space.

“This amounts to a subsidy of more than $50 million per year for all the parking in downtown Hartford,” says Norman Garrick, associate professor of civil and environmental engineering. “To put this number in perspective, all the real estate downtown contributes just $75 million in municipal revenues each year. In contrast, the subsidy for parking in downtown Cambridge, Mass., amounts to just over $1 million per year on municipal revenues of $50 million.”

Cambridge also taxes parking garages at a higher rate than Hartford, while having lower residential tax rates than Connecticut’s capital city. What this means in practical terms, says Carol Atkinson-Palombo, assistant professor of geography, is that “Those who live in Hartford are effectively subsidizing those who work there.”

Of the six cities studied, three – Arlington, Va.; Berkeley, Calif.; Cambridge, Mass. – saw little or no net increase in parking in their central business districts during this time. In the other three cities – Hartford, Conn.; Lowell, Mass.; and New Haven, Conn. – parking grew at a prodigious rate while jobs, residents, and retail generally shrank.

These numbers should set off an alarm for any city, the researchers say, but especially for places facing stiff fiscal challenges. Older cities that have embraced the automobile have an opportunity to boost municipal revenues by taking a different approach to parking.

Fortunately, as Garrick points out, “many relatively pain free steps can be taken.” For example, a city can start by looking at its tax structure to see if parking is taxed at a disproportionately low rate relative to other uses, he notes. Such a tax structure provides a perverse incentive for developers to take down buildings and increase the amount of land covered by parking lots and parking garages.

Chris McCahill, a senior associate at the State Smart Transportation Initiative and a former research assistant in the UConn Department of Civil and Environmental Engineering, says that changing the tax structure to encourage development, rather than parking, can help attract new residents and businesses.

Conversely, he notes, “Considerable evidence suggests that excess parking is a key factor making cities less desirable and less attractive.”