How much is too much for a transit parking garage?

Parking fills up early at stations like Puyallup, but at what price tag should we add more garages? (image: Sound Transit)

Several future parking expansions for Sounder South stations are projected to come in far above earlier cost estimates. On Thursday, the Sound Transit Board is expected to approve a 675 stall garage at Auburn Station that will cost $120 million, 54% more than the previously approved financial plan.

At Sumner Station, Sound Transit intends to spend $81 million for a 623 stall garage, 41% above the earlier estimate. Sound Transit is selecting a project to be built at Kent Station, where the cost of a 534 stall garage has grown to $117 million, already 29% above the previous estimate.

The price tag per stall is extreme. Each of these planned structures are on sites with existing surface parking. At Sumner, the cost is $160,000 for each of the 505 net new stalls. In Auburn, the 555 net new stalls will cost $216,000 each. Even these dizzy numbers pale in comparison to Kent station where Sound Transit plans to spend $278,000 for each of the 420 net new stalls.

Cost estimates for Sounder South parking expansion (slide: Sound Transit)

A fourth project at Puyallup station that begins construction this year is a comparative bargain promising 665 spaces for a project budget of $79 million. At $119,000 per stall, it is the only project of the four with an approved baseline budget.

The construction market was, at least until a few weeks ago, running rather hot in the Puget Sound region. But these costs are far out of line with private sector development. Construction costs can't explain the price tag for new parking in North Sammamish. A simple surface lot with 200 spaces on a green field site has a $23 million project budget. That's $115,000 per stall. Two of the three sites on the shortlist would need structured parking, necessitating third party funding to hit even that budget.

Most transit parking outlays are buried within larger project plans, and the cost of the parking alone is often obscure. The SR 522 BRT project, for instance, includes a commitment for several parking structures for 300 cars each. In Kenmore, Sound Transit is funding a 2 level garage with 187 stalls on each floor. Because it replaces an existing surface lot, and because the site is being optimized for future transit-oriented development, the net addition of parking is only 115 stalls unless third party funding is found to add more parking levels. The cost per added stall is likely to be extreme.

Design concept for BRT parking garage in Kenmore (slide: Sound Transit)

Many readers of this blog will be skeptical of parking expansions, preferring housing or other uses for scarce land near transit stations. But one doesn't need to rehearse those arguments to acknowledge these projects are extraordinarily costly. How much is too much for a parking stall?

Sound Transit is facing newly constrained finances as the economy slows. The search is on for ways to manage lower revenues with the minimum of delays to major project delivery. Unless parking costs can be brought in line with private sector norms, these garages should be deferred or cancelled.