A Minneapolis Councilwoman's Land-Use Masterstroke

Saw this quote in this article:

The Minneapolis policy, proposed by Council Member Lisa Bender, would eliminate all parking requirements for new residential units built within 350 feet, or about a block, of bus or rail service offering frequent, all-day service (every 15 minutes at midday). Within a quarter-mile of frequent bus service and a half-mile of frequent rail service, the policy change would eliminate all requirements for buildings with 50 or fewer housing units, and reduce them to one space per two units for projects larger than that. For developments within 350 feet of infrequent bus service—coming only 30 minutes at midday—the policy would reduce current parking requirements by 10 percent.

Mrs. Bender is truly brilliant. Not only is she proposing what is perhaps the most progressive parking reform in the country, she is doing so in such a way that ties parking to mass transit accessibility. IOW, the closer you are to mass transit, the less parking you need.

She isn't just proposing a law, she's proposing a template of a law. One that can easily be replicated anywhere with a good mass transit core.

For instance, if you applied a similar requirement here in Philadelphia, the scale of our core network is such that parking requirements would be waived entirely for the overwhelming majority of the inner city. It would look not dissimilar to Yonah Freemark's map of Chicago parking requirements.

Bouncing around my mind

Pertinent to this post:

Since the PPA has no inkling of what the actual supply of any of their permit zones actually is, they routinely issue far more permits than spaces that can possibly handle those permits. Anecdotal evidence (courtesy a certain foulmouthed blogger) suggests, for example, that PPA Zone 4 currently has ~2x the permits its physical constraints can possibly handle.

Their ignorance--abetted by the fact that one has ever found a way to assess onstreet supply (until now)--is the only way they can get away with this. The implicit guarantee of a permit is that you are entitled to a place to park in the area where it's issued; if you have more outstanding residential permits than residential spaces, you've reneged on that implicit guarantee. Hint hint.

A Small Estimator for Neighborhood Parking

I've been working for some time on a high-grade parking estimator, and I'd like to share a simpler (albeit less accurate) variant. This estimator will give you, with a quick parameter valuation, a result to a single order of magnitude of accuracy; however, it is quick and useful to have on hand at, say, neighborhood debates.

It is written

where f stands for the count of faces on a unit block, b stands for the count of blocks in the area under estimation, l is the mean blocklength, τ (tau or "taff") is the length of a typical onstreet space, and þ ("thorn") is the ratio of space used.

Assuming FPS, I usually set τ to 15 feet (this I call my "template" parameter) and þ to 0.75 (the "G-Ho" parameter). b is geographically determined, and f by the overarching pattern of block development. Due to our use of grids, it is most often 4. This just leaves l, which is strongly locally determined. For example, in rectangular grids (like Manhattan's), it is the average length of a block from building line to building line; in more regular neighborhoods, a typical side should suffice.

Underestimation

Since this estimator is a highly simplified version of my estimator model, it follows it has a few inherent weaknesses. The largest is a tendency to underestimate, since it fails to count interstitial streets. Most attempts to rectify this without recourse to the full estimator would require significant transformations, subdivision, and general increasing unwieldiness. Because of this, the user must--especially in a neighborhood populated by a high count of interstitial streets--assume that the model has underestimated by an order of magnitude. Yet the results attained from this estimator are significantly higher what most people realize.

Overestimation

The need for τ is obvious, but (unlike the larger estimator) there is no way for this small estimator to autocorrect for deficiencies in its setting. Since the template setting of 15 (feet) is "tight", yielding the smallest standard parallel-parking space, this can also create overestimation, especially in the first part; changing the value of τ also has ripple effects that create larger and larger deviations from the larger estimator--particularly since þ, the G-Ho parameter, is a plug-in of a result attained from the larger estimator with a τ of 15.

In my judgment, however, the underestimation effect is an order of magnitude greater than the overestimation.

To a Higher Grade

While this "small" estimator is a derivation of a much higher-grade one, I must stipulate that use of the latter requires plugging in significantly more data, and therefore comes with a contract requirement. If you or your organization wants to have your parking supply estimated, feel free to contact me; this small estimator can get you into the ballpark, but I can bring you into the infield.

Comments Extracted

Part of a discussion between Jon Geeting and I on Next City piece "It's Time to Cap and Trade Parking Permits":

Me: Jon, thanks for the excellent article. Since I'm sure the data I've collected on SWCC's parking supply formed part of its inspiration, I'm happy to offer a few comments:

1. My first gut reaction was that it was going to be a bad idea. The image the policy's name conjured in my mind was of what would be a wholesale privatization of the (already subsidized) onstreet parking spaces. Reading through the plan eased my fears somewhat, but I believe it is important that a permit is not tied to the space itself (again, because that would amount to wholesale privatization of street space).
2. An issue going forward would be maintaining a certain amount of flexibility. For example, if a neighborhood wished to convert a street to a woonerf, that would entail the removal of a certain amount of spaces. The system you propose increases the flexibility to do this somewhat relative to the status quo (by changing the cap), but increasing administrative layers and distance from neighborhood concerns would increase opportunities for vetoes of changes. So you could go to the PPA and say "here's a close estimate of the parking inventory in Neighborhood X, cap permits for the neighborhood at that estimate", but later changes to the inventory (either for net loss or net gain of parking spaces) would not be so easily ascertained at a citywide level.

What I am getting at is that, under a good cap-and-trade system, permit control needs to be devolved to the neighborhoods--or, more accurately, neighborhood investment districts. (Cf. Shoup, and his work on parking spaces in commercial districts.) This way, a neighborhood would have a dedicated funding stream*, control over how many spaces are permitted (so as to remove them as it sees fit), and an ability to assess parking demand of redevelopment projects...

No, I am not just saying this make myself more work ;). I am also saying this because it's the right thing to do--devolve power over a commons to the most local "stakeholders" (much as I detest that term).
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*Assuming permits are periodically reissued...this is an idea that needs a bit more work.

Jon: I completely agree that the permit should not be tied to the space itself, and should be free to migrate to the areas of the city where there is more parking demand, and cut car ownership in areas where there is less.

For example, I imagine that some of the most central neighborhoods would tip to a lower car ownership equilibrium under this plan, since many of these folks probably use their cars infrequently, and could get several years' worth of Zipcar membership paid for by selling the permit.

I am torn on the issue of whether we should use the Planning Districts as new permit zones, to make sure they don't all migrate to the more auto-oriented areas of the city, or if I think that would actually be a feature of the plan.

Not sure I agree with your assessment of the political economy of the parking removal example. Suppose that under the cap and trade policy, some group pushes to enact my somewhat radical plan for the Bainbridge Green, which would take away about 175 parking spaces.

On one side, you'd have a lot of people who would not want those spaces to go away. But on the other side, you'd have a group of people whose permits stand to get more valuable if 175 spaces go away, since a tighter market would make the permits more valuable. You might have some people showing up to support the new park just to increase the value of their assets.

Could you also elaborate a bit on what you have in mind for neighborhood control over "how many spaces are permitted" and "assess parking demand of redevelopment projects?" My preference would be to stop printing permits altogether, starting ASAP, and let people work these things out on an informal market. I'd like to get the city out of the business of assessing parking demand altogether, and leave it to housing and parking garage developers to gauge how much parking demand there is, and how much people are willing to pay for it.

I see it as an opportunity to reorient the political economy of development around a much lower car ownership equilibrium. I would expect to see a cycle of more infill development in the high-demand areas, followed by growth in transit ridership, and a subsequent sell-off of permits, with permits filtering outward through the successive neighborhood rings over the years.

Me: 1. I agree with your last paragraph.

2. As you may recall, I found that there is a very physical maximum of possible parking spaces in a neighborhood. Beyond this limit, any further permit you issue devalues the parking space.

3. What I have in mind is for a neighborhood to have local control over its parking. Among other things, this means that I would devolve (onstreet) parking permits from the PPA and into the hands of formally-recognized NIDs (there would be certain basic conditions tied to demonstrations of competency, like paid staff, the ability to maintain space inventory, and a certain amount of liquidity *necessary to hire a certain reasonably-priced consultant, heh*). Because parking permits are thus controlled and managed at the neighborhood level, parking policy--and hence transportation policy--comes to be managed at this level, too.
(This is not to downplay the need for a citywide transportation policy, but rather is meant to reflect that most transportation needs are best locally determined; I imagine we could build the system such that the City can exert its natural claim to street space if they wish to put e.g. a protected cycle track or bus bumpout in.)
This limits "migration" more than your proposal, but I don't see that as a bad thing in and of itself, as neighborhoods like Mayfair and Oxford Circle don't have remotely close to the same kinds of supply/demand issues neighborhoods like SWCC, Fairmount, or Bella Vista do. Heck, even Whitman doesn't have the same level of parking issues.

4. Note that I said that one of the measures of competency a neighborhood organization (usually an NID, although other high-compentency organizations such as SOSNA or NLNA should also qualify) has to show to control its parking is an inventory. This is because (a) a strong, well-maintained local inventory will be able to capture minute changes in parking supply, and (b) the group controlling that inventory can use it to further their own goals.

For example, say that a group wished to make Bainbridge Green green. They could then either (a) organize in a bid to control Bainbridge Green's parking inventory in order to reduce/eliminate it, or (b) work with another group, such as the QVNA or a QVNID, which would have a parking inventory (~2000 spaces as a first-order estimation) including the 170-odd spaces on the "green"...

...At this point I find a particular difficulty between your idea and my work: My work is based on the idea (a long-term policy goal, actually) that parking should be treated as a neighborhood "commons" and thus come under the control of that neighborhood. While this is not directly in opposition to your idea, significant difficulties exist in co-implementation. My hunch is that both of our ideas ultimately result in the same end-state: they just come to it differently. (An NID that derives most of its income from parking permits has a significant incentive to optimally price those permits i.e. make them a scarcer commodity i.e. reduce inventory. This is in agreement with Shoupian devolution of Main Street metered spaces to BIDs; they're the ones with the most incentive to get things right.)