Friday, June 15, 2012

Residential street parking

We have a love-hate relationship with street parking in cities. On the one hand, it's convenient when available, it provides a safer way to use up space on overly wide roads, and offers some potential protection from moving traffic. On the other hand, it's almost always short in supply, creates potential blind spots where children might be present, and becomes a flash-point in neighborhood discussions about new growth and development.

A common theme I often hear at community meetings and read in newspaper articles about proposed new buildings is: "what will happen to our street parking?" And I don't just mean through changes to the streetscape. Folks at these meetings are worried about losing "their" access to street parking because of added "competition" for finding spaces. The sense of ownership that residents exercise over pieces of the public right-of-way becomes an impediment to necessary changes and growth in the neighborhood. It's a perverse situation that comes about because of the confused nature of the not-quite-public and not-quite-private feature of street parking. And there will always be political pressure of this form as long as street parking is permitted, because of the basic geometry of streets and blocks.

What do I mean? Well take a look at the example block from the North End I have shown above. According to the census, there are 173 dwelling units and 293 people living on this block, mixed with a few shops, which encompasses approximately 1 acre of land. There are 37 parking spaces distributed around the perimeter of the block. There is also a garage underneath one of the buildings, and I don't know how many spaces are in there. Still, there's probably no more than 1 parking space per 4 dwelling units. This kind of ratio would never be tolerated even under supposedly more enlightened zoning codes these days. Now, the North End is a pretty walkable place that was urbanized centuries before the automobile became dominant.

Very close-by is another example where over half a block was leveled to build a parking lot. The density is on the remaining portion is approximately equivalent to the previous example. The parking lot employs a valet who double-parks the cars, providing at least 80 spaces without blocking the access lane. The perimeter street parking follows similar ratios, except for the curb cuts. There are 102 potential parking spaces visible in this picture, giving a 2.5:1 ratio of spaces:dwelling units. So it is likely that some of the residents of other blocks use this parking lot to store their cars. There still must be a high proportion of residents who walk and use public transit exclusively, though. And thankfully, since most of the North End does not look like this, that kind of lifestyle fits in well.

This example comes from South Boston, which is far more car-oriented than the North End. Again, the entire block is about 1 acre, but this time there are only 43 dwelling units on the block. This is largely because the buildings are shorter, being only 2-3 stories instead of 4-5 stories, and some other design differences. There are 35 street parking spaces and at least 9 off-street spaces (maybe more with double-parking). That's a 1:1 ratio. Although there is a frequent bus route less than a quarter-mile away, it is likely that every apartment here has at least one car (the exception may be caused by the upper-right corner, which appears to have its off-street spaces devoted to that one set of units). One curiosity about this particular block is that the side streets are actually smaller than those shown in the North End example: there is only space for parking on one curb. In general, most South Boston streets are much wider than North End streets. That means the adjacent block shares street parking with this block. There is a larger off-street parking lot on one of them, which probably helps to make up for this.

The density difference is pretty stark between the North End and the South Boston examples. The 171 dwelling units per net acre of the North End produce a very urban, walkable neighborhood. The 45 dwelling units per net acre of the block in South Boston, which is fairly typical, falls in a range which still drives people to use their car for most trips. And it results in some of the most ferocious fights for street parking in the country. If you require every dwelling unit to be paired with some street parking availability, then you are going to be restricted to this 40 unit per acre maximum. And unfortunately, it seems that this number is simply not enough to generate sufficient city vitality in most cases.

Suppose you decide instead to end the practice of street parking, as is done in Tokyo. Is one solution to allow developers to sacrifice the first floor for a garage, San Francisco-style? It can potentially squeeze more cars into the same space and not sacrifice as many dwelling units. But if you force every parcel to be like this then what you get is a lot of nasty curb cuts and the garage wall effect. And then people loathe walking in such a place, it encourages driving everywhere, and the streets become dangerously clogged with cars.
"Garage wall" effect (src: Old Urbanist)

One possible way to alleviate the speeding problems is to make the streets Japanese-style, no more than 10-14 feet wide. You can do away with the curbs and share the streets with people, eliminating that problem too. Plus, that can make up for some of the space lost to parking garages, since asphalt coverage will be under 20% or so. That still doesn't eliminate the garage wall effect, but that could be made up for in more creative ways.

Seijo street (src: Nathan Lewis)
The important part is that nobody should be forced to build parking. Spaces would be just another piece of floor area for sale or lease. Owners of parcels near good public transit may find it more economical to not build parking, while those of parcels far from good transit might choose to add extra. With parking on the free market, there's nothing stopping a person living in one building from renting or purchasing a space in another, nearby parcel. Indeed, just a few months ago, one developer offered to make that kind of arrangement within his own properties on one block here. There's no reason why that shouldn't be more common, treating parking spaces as a commodity, to be bought and sold on the market -- instead of being forcibly supplied by overbearing regulations.

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