Tomorrow is the last day for one to submit comments and take a survey on Sound Transit’s Draft North Corridor HCT scoping document. The corridor’s aim is to serve North Seattle and Lynnwood and the mode will almost certainly be light rail, but by law Sound Transit is going through a more general alternatives process so North Link will be eligible for federal New Start funds. The truly largest unknown for this project is which alignment alternative is the best: along I-5, Aurora Ave, or 15th Ave.
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Each alignment has its own advantages and disadvantages that should become clearer as this process moves forward. Sound Transit has already studied these alignments in an issue paper. While the paper is a good starting point, there are still many unknowns.
All three alignments would serve stations at Northgate, Mountlake Terrace, and Lynnwood — the difference is what happens in-between. Below I’ll outline what the three alternatives could look like and some advantages and disadvantages that I see for each. More after the jump.
I-5 Alignment (Red)
- Runs along the side of I-5, switching from the east side to the west side around the county line.
- Stations at NE 145th and NE 185th. These station areas are fairly constrained by single family neighborhoods (and a golf course at NE 145th) with very little space for P&R garages and virtually no TOD potential.
- End to end travel time is lowest.
- This alignment roughly splits the difference between the high demand corridors of Aurora Ave and Lake City Way, requiring all riders to either drive or transfer from a feeder bus.
- Because of I-5’s ramps, sound walls, detention ponds, limited ROW, and bridges, I could see this alignment being more complex and costly than one would expect.
Aurora Ave Alignment (Blue)
- Runs up Aurora Ave after transitioning over from Northgate Station somewhere between NE 103rd and NE 130th. At SR-104 it would turn east and meet up with I-5 at Mountlake Terrace.
- Although Sound Transit previously identified only two stations, I believe three stations along Aurora Ave makes more sense.
- The first station after Northgate would probably serve the Bitter Lake neighborhood at or around NE 130th.
- The second stations would probably serve the Aurora Square Shopping center and Shoreline Community College somewhere around NE 155th to NE 160th.
- The third station could be somewhere between NE 185th and SR-104.
- End to end travel time would probably be 1-3 minutes longer than the I-5 alignment.
- These stations have enormous TOD potential, with large underutilized and under-performing commercial lots that are perfect for significant upzoning and redevelopment on the scale of Bel-Red corridor of East Link. Bitter Lake has already seen significant senior housing development in the area.
- The width of the road and commercial character make an elevated alignment down the corridor viable, which would be required to maintain reasonable travel times.
- The federal transit funding landscape has changed dramatically over the last few years. The federal government has finally gotten the message that land use and transit must go hand in hand. As part of this move, the FTA has relaxed cost-effectiveness rating which focus on travel-time savings — a pro-suburb metric — at the cost of livability. While cost-effectiveness is still one of the six measures used to rank New Starts projects, other goals such as transit-supportive land use policies and future patterns, mobility improvements, environmental benefits, operating efficiencies, etc. are now given more weight. While we have to wait for more information before we can have an informed discussions about some of these goals, an Aurora alignment easily wins with regard to TOD.
- From a network design perspective I particularly like an Aurora alignment because it seamlessly merges Seattle’s two largest North/South transportation corridors. Despite Aurora and I-5’s close proximity — roughly a mile — connections between the corridors are horrible, especially for transit riders.
15th Ave Alignment (Green)
- Runs up 15th Ave probably via Pinehurst Way N. The north end of this alignment conveniently joins with I-5 close to Mountlake Terrace.
- Sound Transit is looking at two stations, probably at NE 145th and NE 175th. These are largest activity nodes along the corridor.
- The issue paper says this alignment will take 4 additional minutes compared to I-5 — even with an elevated alignment, which doesn’t make sense to me.
- This alignment a mixed bag, with less extreme disadvantages but also few large advantages. For example this alignment has modest TOD potential compared to Aurora but won’t have the same P&R opportunities as I-5.
- 15th Ave is a narrow corridor with single family housing all along the corridor, making an elevated line fairly hard politically.
- From a long range planning perspective, 15th Ave is bad. It puts Link in an awkward, no mans land; it’s half-way between I-5 and Lake City Way. This creates problems similar what Martin wrote about yesterday in the Rainer Valley.
These three options are the main alignment alternatives on the table, but the process is just getting started. Stay tuned over the next year or so. Just like with the First Hill Streetcar and East Link, you can expect different interests battling over different alignments. We’ll try to weigh in over the coming months to help you navigate the process.