Press Releases

Never Enough Parking Spaces

Did you drive to work this morning? Was a parking space waiting for you when you arrived? Many cities require developers to provide a minimum number of parking spaces for office, retail, and residential buildings; sometimes the number is based on the square footage of the building, sometimes on occupancy. Many calculate the required number of spaces based on peak demand. As this article from the Economist notes, some cities ask for what seems like an excessive amount. Cupertino, CA—home to Apple's new headquarters building—requires two parking spaces per apartment, one space for every three seats in a fast-food restaurant, and seven spaces per lane in a bowling alley (plus more for employees). Apple's headquarters will have 11,000 parking spaces for 14,000 workers, and the parking will take up more area than the offices and laboratories.

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Another thing parking does, although the Economist article doesn't mention it, is add impervious surface to the landscape. This article from Stormwater by Lisa Nisenson and Clark Anderson suggests that cities reviewing their ordinances and codes can and should eliminate excess parking: "Like street design, parking occupies a conspicuous spot on the impervious audit radar. Almost all code reviews recommend reducing the amount of parking in standards. However, there is no magic code change wand that reduces spaces without some pushback from retailers, landowners, and stakeholders concerned about spillover parking. We found that successful efforts often began with parking space utilization studies. These studies look at the degree of over- and undersupply, how to handle peak parking events, and management options within a 'parking-shed.' Parking studies usually initiate a broader effort to 'find' parking spaces on existing paved areas. Even so, there are a couple of quick fixes. For example, basing parking requirements on staffed space rather than gross square footage can reflect demand while reducing spaces needed."

The Economist article notes that after London got rid of parking minimums altogether in 2004, essentially letting market forces decide how much would be available, the number of spaces in residential areas actually dropped. In general, eliminating excess parking is a good thing, not only in terms of managing stormwater but in making a city more livable: "The more spread out and car-oriented a city… the less appealing walking and cycling become," the article points out. "Parking influences the way cities look, and how people travel around them, more powerfully than almost anything else".

Cities with minimum parking requirements also make things tough for redevelopment and infill projects, which often don't have enough land available to satisfy them. Going underground is not an attractive option, either: "Creating the minimum number of spaces adds 67% to the cost of a new shopping center in Los Angeles if the car park is above ground and 93% if it is underground." And everyone—even those who rely on public transportation—subsidize that parking by paying more for restaurant meals, theater tickets, and retail goods.

It's a fine line, though—what happens when there's not enough parking? Drivers spend time and gasoline—and get frustrated and angry—driving around searching for an empty space. By one estimate, cars in Los Angeles' Westwood area, which has very few spaces, drive an additional 950,000 miles per year just in the quest for parking spots.

By Janice Kaspersen

Bite Size Solutions To Large Problems

As with many other cities that have combined sanitary and storm sewer systems, Chicago has a combined sewer overflow problem, with an average of more than 60 overflows a year. And, as many other cities are doing, it's turning to green infrastructure to help solve the problem—infiltrating as much water as possible to keep runoff out of the now-undersized and overburdened sewer system during storms. In addition to traditional methods of dealing with runoff and wastewater, Chicago and other cities are looking to smaller, decentralized solutions.

Chicago has taken some early and visible steps toward green infrastructure, such as its Green Alley program 1 and the famous green roof atop its City Hall 2. One thing the city is doing that some others are not is taking active measures to see how well green infrastructure is working. It's notoriously difficult to do.

Several years ago, Gordon England wrote an article 4 for Stormwater magazine outlining how more widespread use of green infrastructure (then commonly referred to as low impact development) would affect municipal development processes, as well as the difficulties of inspecting and maintaining these widely dispersed installations. Who's responsible for long-term maintenance on single-family residential properties, for example? The city, the homebuilder, the homeowner, or some combination?

Maintenance is only part of the question. How can we be sure the many individual green infrastructure measures—bioswales, areas of permeable pavers, and so on—are removing as much volume from the system as intended? Even with the best design, who's checking to ensure they're still working as efficiently as they should after several years—that the media in the rain gardens and swales hasn't clogged with silt, or that some of the residential rain gardens haven't been completely replaced by the homeowners?

Questions like these make some strong proponents of LID and green infrastructure touchy, as we've seen from the responses to England's article and others. But they're necessary, and Chicago is asking them. Quoted in this article 5, Marcus Quigley, CEO of Opti, sums up the problem: "One of the challenges…is that you have these vast numbers of small assets, and green infrastructure makes this problem infinitely more challenging than the historical approach to having large civil engineering projects that deal with stormwater. Instead of having a million-gallon tank, you may have several-thousand-gallon bioretention cells to store and treat this water. And those assets are much harder to track."

His company and others have collaborated on a system called Smart Green Infrastructure Monitoring (SGIM), led by UI Labs. SGIM involves a network of above- and below-ground sensors to monitor everything from weather conditions to soil moisture and various water-quality parameters. It's still a work in progress, but data will be sent via a cellular network to help determine how various installations are working—"the quantity of water, how it flows, and if it's flowing," says Quigley. Ultimately, the goal is to allow real-time monitoring of different types of green infrastructure in different locations around the city to see which measures work best under particular conditions, and to alert the city when something isn't working as intended—clogged with particulates or trash, perhaps. The data will be available to the public and should help developers and designers—in Chicago and in other cities—figure out what will work in their own situations. As green infrastructure measures become more widely adopted, and in some cases required, this is the kind of thing more cities should be doing.

By Janice Kaspersen