How parking shapes urban form

I noted a few posts back that I’m reading the book “Edge Cities: life on the new frontier” by Joel Garreau, at the moment. The book is broken up into chapters that focus on a particular place, although within each chapter is a wide variety of information about how edge cities function, why they exist and details on particular examples of them.

Of particular interest in the chapter on Detroit is an explanation of how key a role parking plays in the structure and shape of edge cities. In fact, parking seems to be the driver for pretty much everything about how the Edge City is shaped and how it functions – interesting to note when you consider how planning generally ignores parking to a large degree (aside from making stupid rules that are backed by little logic).

The developer’s rule of thumb is that in Edge City, there must be one parking space per every worker. Because one employee uses about 250 square feet of work space and each car requires four hundred square feet to be parked, there has to be about one and a half times as much space to park the cars as there is to nurture the drivers.

If the developer does not provide that much parking, he will have grave difficulty getting bank financing. His project will not be judged commercially viable. In fact, in many Edge City jurisdictions, the developer is required by law to provide that much parking. The lawmakers don’t’ want people to park on streets and lawns, either. Their experience, too, has led them to believe that one worker will equal one parking space.

Essentially, with the ‘everyone will drive to work and therefore everyone needs a parking space’ motto that defines the Edge City (and Auckland’s parking policies) we find ourselves in the rather bizarre situation of providing 50% more space to the storage of vehicles than we provide for the actual undertaking of economic activity which occurs within these places. The ratios seem to hold true in recently developed commercial centres in Auckland, like Manukau, Botany Town Centre and Albany. In these places, parking is the dominant urban feature – presumably because both our planning rules have required it to be and there is the feeling that each worker must be provided with a parking space (for retail areas, I’m guessing this is translated into each shopper).

Given the assumptions above, if we provide parking through multi-level structures or underground, we can increase our densities – but this comes at a pretty high cost. Auckland Transport is effectively trying out this approach in Manukau, by building parking structures to encourage the freeing up of surface parking for development – at an enormous cost.

The book continues:

…the cheapest option a developer has is this. Build a one-story building. Let it cover 40 percent of the ground. That leaves 60 percent of the land to be covered with a simple parking lot. No grass or trees or sidewalks. But the right ratios at the least expense. Which explains why an awful lot of cheap development looks the way it does.

This kind of construction guarantees that all buildings and people will be about as far away from each other as physically possible, surrounded by fields of asphalt. This in turn guarantees that the area so built will be an aesthetic and functional sump.

Places like Westgate, Smales Farm, Apollo Drive (near Constellation Drive) as well as the usual suspects listed above come to mind when you read out this description. The developers have simply followed the parking requirements and created what makes most financial sense. All other planning rules have become effectively irrelevant and you end up with this:

But not every Edge City follows this simple formula – cheapest isn’t always best:

That level of development is only the cheapest kind, not necessarily the most profitable. Buildings laid out like that do not command much rent. If the land in that Edge City is expensive, and the developer puts a small, cheap building on it, he will go bankrupt.

So he may decide he needs to bring in more revenue. To do that, he would want to build more office space on the land. This would require him to make his building wider or taller or both.

This sounds easy, but it present a serious problem. More building kicks all his cost calculations into a new orbit. He needs more parking to match the increased amount of office space. But he has run out of land. Therefore, he must build a multilevel parking “structure”. That will cost more than twice as much per parking space as his initial calculations. That levitates his cost, which requires that he build his building larger still – in order to break even. This, in turn, requires more parking, and so the spiral goes.

What all of this means is that to get a floor-area-ratio (FAR) of more than 0.4 (which, in urban areas and particularly town centres, is very low) life gets really tricky for developers if they are reliant on providing every single person who travels to the area with a dedicated parking space. Look at most of the new retail and office areas of Auckland and you can see the effect of this: more space dedicated to storing cars than to actual buildings. Relatively low employment densities. Poor agglomeration economics. And so forth.

The book doesn’t make this conclusion, but I think that the numbers above highlight the importance of improving public transport – so we can grow our employment numbers and density without ending up in the ugly spiral of parking costs and building size. If we can get more and more people to town centres via ways other than driving, perhaps the biggest benefit we create is through the freeing up of land for more productive uses than car storage. Of course our parking rules need to change as well, because even now we generally force an over-provision of parking (partly by requiring each individual use to provide for its own parking requirement and not allowing the sharing of facilities).

I wonder if the economic benefit of reduced land requirement for parking is measured in the cost-benefit analysis of public transport projects? Similarly, one wonders whether the economic disbenefit of roading projects which encourage more people to drive to an area and park in it, are captured. With parking at the crossroads between land-use and transport policies, it seems to be utterly critical in shaping our urban form.

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