Basically, the premise is that you never need all the parking required for a mixed-use development because different users need parking at different times. At night, residential and retail users need spaces. During the day, retail and office users need spaces. So the residential and the office users can share spaces. Obviously, some number of apartment folks will not be gone during the day, or will leave their car at home for whatever reason. So you can't share all the spaces. But you can share some of them.
Obviously, the success of shared parking depends a lot on the math for individual projects. Let's look at 315 W. Ponce, since I've been talking about it. First, let's assume that everybody who ever needed to park at 315 W. Ponce needed to park there at the same time:
|Maximum use |
Like I said, you won't ever need all of these spots. During the day, you need enough space for all your office folks, plus all your retail shoppers. How many spaces should you keep for the folks who leave/need their car at home during the day? The parking study assumes that 40% of apartment folks will keep their cars at home. Let's see how that looks:
|Day-time Peak Use |
|100% office users||240|
|40% residential users||132|
|100% retail users||35|
This is how they end up justifying a 428 space parking deck. They've even included at 21 space cushion, in addition to the 22 surface lot spaces that will be left after redevelopment. I think 40% is quite a reasonable assumption, but if there is a weak point here, that would be it. Still, I would not want to be the one arguing that half of the residents would need to leave their car at home all day. It wouldn't look like any apartment complex I've ever seen.
What about at night time? This is beyond the scope of the 315 W. Ponce parking study, but let's go through the same procedure. Let's assume that 20% of the office workers stay late and need to park their cars in the deck in the evening. Then, let's factor in all the residential users and all the retail shoppers:
|Night-time Peak Use |
|20% office users||48|
|100% residential users||330|
|100% retail users||35|
We are still under the 428 spaces in the deck. This is why 315 W. Ponce won't create excess parking issues for the neighborhood.
For statistical junkies, the parking study uses existing traffic counts for the office building and a 1.5 space/unit, which is actually greater than the 60% one-bedroom unit mix might need. For a 1 space/bedroom ratio, they would only need a 1.4 space/unit ratio, or 308 spots. The extra spaces accommodate guests, but if a developer were trying to "cook the books" on parking numbers they could do so here. The fact that they don't suggests they are on the up and up. The study also uses a 5 spaces/1,000 sf of retail, which is typical of retail projects. Some urban projects try and get away with less, counting on people walking, etc. The ratios here is also very dependent on what type of tenants.
The more I look at these numbers, the more I think the opposition is about any development on this site, period. The argument about excess parking doesn't hold water, in my book, although I guess that is up for debate. I think the parking study is very reasonable, and I find the objections overwrought.
Decatur Metro has a good post explaining why this site in particular is special. I for one would appreciate a discussion on the merits of infill development in historic areas, instead of arguing over the finer points of New Urbanism. As it is, the opponents come off as obstructionists and bullheaded, which is a shame. I am sure there are good points to be made about the historic nature of the area that are unrelated to the parking issue, but they get overshadowed because the neighborhood has chosen to make their stand on parking.
Of course, feel free to ignore me. Apparently because I own a car I can't talk about this stuff.