Maybe local governments don't really need to require parking itself. Maybe they could simply require POTENTIAL parking?
I am imagining a municipality that still wants to make sure parking supply meets demand and wants to avoid the risk that the parking associated with a new development spills beyond its parking lot into the streets or into neighboring lots.
I can imagine a conservative version of this idea, in which a city allows developers to have less parking than the current minimum but the city reserves the right to later (and at short notice) require that the on-site parking supply be increased (up to the current minimum for example) if there is evidence of any serious spillover. Such a policy would allow developers to start with modest parking supply but they would have a strong incentive to design their sites in ways that allow parking to be easily expanded.
A more ambitious and reformist version could simply require that the site have a certain amount of 'potential parking' (space which could be 'easily' converted to parking space) but then leave it to building managers whether they ever actually do any such conversion. This would be closer to a Shoupista-style deregulation and abolition of parking requirements, except that the risk of getting locked into a serious shortage is reduced. Of course, we would need to define what we mean by 'easily' converted.
This is not a new idea, by the way.
It seems to be an old one which has been forgotten. The suggestion to require convertible space rather than parking itself was apparently first made by a young Gabriel Roth in his 1965 Hobart Paper, Paying for Parking. Roth's paper should be downloadble via VTPI - go to the bibliography at the bottom. However, I can't get the link to work right now so maybe it is broken.
I think the idea deserves more attention and debate.
Does it sound feasible to you? Could a suburban municipality be open to requiring potential parking instead of requiring parking itself? If anyone knows of any analysis of this proposal or something similar I would love to hear about it.