I was all set to slay Sound Transit for leasing 103 parking spaces in Edmonds for $150 per month each, following a news cycle of recriminations over high operating costs. Park-and-rides are necessary evils, good money after bad, and all that. But when I sat down and worked out the numbers, I found that it may be one of the more cost-effective things an agency has done in a long time.
Let’s build a little model with the following assumptions:
- Every space is full and brings a single rider, or two boardings. No carpools.
- Each boarding generates the 2011 North Sounder Average of $3.30, as stated in the 2011 Fare Revenue Report (p. 24). Edmonds is the lowest fare to Seattle, so that’s probably a slight overestimate.
- None of the lot users previously walked, biked, kiss-and-rode, carpooled, or took the bus to the station because it was too hard to park. We simply don’t have the data to evaluate this properly, though I suspect this is more true than not.
- The marginal cost of carrying a rider on the train is zero.*
Assuming 255 work days per year, the parking contract comes out to $3.55 per boarding, meaning the net subsidy is 25 cents per marginal ride. That’s an order of magnitude lower even than putting on another bus, providing lots of margin for the model assumptions to be wrong while still making it a relative bargain. It’s one advantage of building attractive high-capacity transit: simple schemes can boost ridership and attract high fares for little or no net cost.
* According to ST’s Kimberly Reason, insurance and 1.96% state tax on fares mean this isn’t strictly true.