Sound Transit and the City of Bellevue have just released their joint analysis (PDF) of the East Link options for downtown Bellevue. East Link project manager Don Billen briefed me (and happily answered all of my questions) by phone on Saturday morning.
Four options were studied, and two come out as rock stars – C11A, a surface option with two stations, providing great walking distance coverage to almost all of downtown Bellevue’s jobs and homes, and C9T, a more expensive tunnel option that provides decent walking coverage of downtown, plus reduced travel times that attract more riders from the east. Both of these alternatives get the segment 8,000 weekday riders in 2030.
The two not-so-good options are losers for clear reasons. C9A, a surface version of the tunnel option, has the same downtown travel time as C11A, but doesn’t compete with C11A in walking coverage, especially as downtown grows. The City’s walkshed maps are similar to what Adam did for our First Hill Streetcar piece, using the actual walking times from the platforms to different destinations via the network of sidewalks and paths, rather than just drawing a circle at a particular distance. As a result, they give a much more accurate view of what’s accessible from a station.
C14E is the other loser – the I-405 alignment that Kevin Wallace has proposed. Analysis found that a circulator bus would offer no significant benefit. It would attract only 6,000 riders, completely failing to serve western downtown.
The real comparison here will be between the better two: what I’ll call the tunnel (C9T) and surface alignment (C11A).
More after the jump
First, on the tunnel: Sound Transit found that if they design the section just south of downtown Bellevue specifically for a tunnel approach, it can save $100 million – bringing the gap between available funding and the cost of a tunnel to just under $200 million. That’s a gap the City of Bellevue could afford to fill.
The tunnel also picks up 2,000 total East Link riders over the surface alignment – for a total 2030 weekday of 51,000 versus 49,000. These other riders are mostly poached from bus service, as this alignment makes travel times to Bel-Red, Overlake and beyond more competitive with 520 buses.
But the tunnel has a downside. Not only does it have longer construction time than a surface option, it would be a cut-and-cover tunnel, both increasing project risk and seriously impacting downtown Bellevue during construction. In addition, modeling shows that it doesn’t do much in the long run to help traffic. A surface route’s impact on Bellevue traffic is negligible – while Bellevue will have much worse traffic in 2030 than today, that would change minimally with or without surface rail. The projection shows Bellevue streets’ 2030 car carrying capacity would be 78% of demand with a tunnel, or 77% of demand with surface (with a margin of error >1%).
In terms of walksheds, the two station surface option looks by far the best. While Adam can speak more to what “matters” here, I believe ridership drops off significantly past a 5 minute walk, so I’m focusing on those numbers. Projecting to 2030, 76% of downtown jobs and 53% of downtown residents will be within 5 minute walk of surface option stations, with 99% and 92%, respectively, within a 10 minute walk.
The next best coverage comes from the other surface alternative (C9A), with a 25 percentage point drop each for only 51% of jobs and 28% of residents in a 5 minute walkshed – you can see how much the second station is worth. The tunnel is seven points below that for 44% and 21%, due to the added time it takes to get underground (yes, the walkshed calculation includes that). And finally the 405 alignment walkshed is laughable – covering only 27% of jobs and 7% of residents.
Fundamentally, there’s a big tradeoff here, and it’s going to be up to the ST Board and Bellevue City Council to determine whether they want to take on the added risk and expense of a tunnel to better serve points east of downtown, or a two station surface option that provides better long-term coverage for growth in downtown Bellevue. Personally, I predict they’ll choose the latter – this analysis shows that there’s only a minor traffic impact, and in the long run, we’ll be happy we built the extra station.