The Seattle Department of Transportation (SDOT) released a much-anticipated report this morning on parking occupancy and new rates for street parking (I already blogged basics about the press conference here). To compare the old rates to the new ones, which will kick in next month, see the black-and-white table after the jump.

In short, the cost to park jumps from $2.50 an hour to $4 in downtown and First Hill, with smaller hikes in other high-density neighborhoods, while rates drop in four lower-density neighborhoods.

Why the change? The city has contended since last fall that higher hourly rates will increase turnover and open up space—because parking downtown is so full that potential workers and shoppers go elsewhere. For example, SDOT spokeswoman Marybeth Turner said in October, "Downtown street parking is at 100 percent capacity for most of the day." This study claims—and the graphic above shows—that peak occupancy is highest in the First Hill (100 percent), the downtown core (97 percent), and Pioneer Square (91 percent).

But the study's findings, at first blush, don't necessarily back-up this claim. SDOT studied 7,800 parking spaces out of the city's total 13,500 parking spaces last November. And what it found wasn't close to 100 percent occupancy. In the city's "commercial core," occupancy was at 84 percent at its highest at midday (between 12:00 p.m. and 1:00 p.m.), 80 percent in the evening (between 5:00 p.m. to 6:00 p.m.), and 88 percent at night (7:00 to 8:00 p.m.).

In other words, the study found that—even under the old rates—we have about 15 percent parking free. That jibes with the advice of Donald Shoup, a UCLA professor of urban planning and nationally recognized parking expert, who recommends 15 percent of on-street parking should be available during peak hours.

So what gives?

SDOT traffic director Charles Bookman says the city assumes the 97 percent occupancy of downtown space by taking the hard numbers and extrapolating other trends: seasonal fluctuation and particularly busy blocks. First, this study was conducted in November, when, he says, parking is about seven percent lower than the rest of the year. "My recollection is that parking occupancy is highest in the summer. Seattleites are nesting in November—they are staying home, it's wet, it's dark," says Bookman. So SDOT has adjusted for this seasonal inflation. (for the record, SDOT did the study in the lowest parking month because the mayor and council wanted the study as soon as possible. "It's not our choice," he says.) Second, Bookman says the rates are adjusted for the most congested part of a neighborhood. All told, the most congested parts of downtown at the busiest times of year would have an estimated 97 percent occupancy—so the city is trying to reach 78 percent capacity on those blocks by increasing rates from $2.50 to $4.00.

Not to get all Crosscut on your ass, but I can't say I'm convinced the hike is necessary for the stated reasons. Sure, I heart the War on Cars. And I'm all for higher parking rates. But based on this study, parking doesn't appear as impossible downtown as the city, Kemper Freeman, and some suburbanites have portrayed. Sure, the worst times of year in the worst blocks may be bad—if these projections are accurate—but the data we have doesn't quite prove a constant, widespread problem. In most of the city, the study finds occupancy is even lower than the ideal 85 percent (and, conversely, that the percentage of free spaces is higher). For instance, even in the worst-case scenario projections, occupancy would still only max out at 85 percent in Pike/Pine. If we want to raise parking rates for the sake of raising revenue, that's actually fine with me (full disclosure: drivers are the enemy). But it doesn't raise much money... only $6 million for this year's budget. Likewise, when mall shoppers people scream murder about the impossibility of parking downtown, I won't be convinced by that, either.

Later this year, the city will conduct a second study, after these rates are in effect, to determine if a block-by-block pricing scheme would serve as an improvement.