In recent weeks, Sound Transit has released several corridor reports for the Eastside. These were previewed in meetings in May and June, but I thought it might be interesting to take a closer look at the options for Sound Transit on the Eastside. The reports offer quite a bit more detail, and some occasional editorial comment. First up, I-405.
Sound Transit has a long-held commitment to BRT on I-405, dating to Sound Move in 1996, and updating the I-405 master plan in 2002. The master plan envisioned all-day service with 10 minute headways along the length of the corridor. Since then, Sound Transit has built a number of HOV direct access ramps on the highway and transit center projects serving local and regional service along the corridor more generally. Most of those are toward the north end of the corridor, in places such as Totem Lake in Kirkland. Practically speaking, this has translated to a set of express services on the highway that are low-frequency outside peak, and subject to reliability issues in the increasingly crowded HOV lanes.
The challenges in serving the corridor are obvious. Development potential in Renton and downtown Bellevue is substantial, but low to moderate elsewhere in the corridor. Most potential stations are park-and-rides far from walkable communities. Building ridership requires more direct access to neighboring communities, but that adds cost and hurts reliability. Travel markets are widely dispersed, particularly at the ends of the corridor. Most trips on I-405 are only a few miles in length. But with 800,000 daily trips on the highway, it’s tempting to look to BRT as a strategy for reducing traffic.
Two representative infrastructure models are analyzed. Combined with two service models, there are four scenarios considered (they briefly discuss a fifth option, a variation in the alignment within Renton). But the infrastructure models are not either/or choices. They are representative models of a portfolio of infrastructure elements, so expect the ballot to involve some a la carte selection from among the individual elements.
The ‘phased build-out’, A3, assumes WSDOT will complete the BRT projects that are currently funded or have been identified as ‘next priority projects’. The ‘full build-out’, A2, assumes several additional capital improvements. It might make sense to think of A3 as one reasonably feasible set of projects for the 2016 ballot, and A2 as a wish-list for the LRP. A2 does depend in important ways on fulfillment of the full I-405 master plan by WSDOT, an effort likely to extend over decades. The incremental projects are mostly freeway stations and direct access ramps.
The incremental projects between A3 and A2 require funding from both Sound Transit and WSDOT. While included in the I-405 master plan, it’s not clear that WSDOT’s priorities will align, or that the Legislature would add funding for WSDOT in Sound Transit’s preferred time frame.
Stations served are mostly in Renton, Bothell, and Lynnwood, so this looks very much like a commuter express for riders to downtown Bellevue, but with much more regular off-peak service than today. Under the A3 scenario, the only Bellevue station served is the downtown transit center. In Kirkland, only Totem Lake is served (the freeway station on 128th, not the more central Totem Lake transit center). So the plan is notably weak in the middle of the corridor.
Under the ‘full build-out’, ST would add stations at Newport Hills P&R, and at 85th St in Kirkland. Those would not be served under the ‘phased build-out’. Newport Hills has an affordable cost of just $63 million, but serves only a 275-car Park & Ride. Serving 85th St is $384 million. That seems due to inadequate space for direct access ramps, necessitating a major rebuild of the highway. As this would be a particularly poor way to serve central Kirkland, it seems unlikely to be built.
The sticker price for Sound Transit is $700-900 million for the ‘phased approach’ and $1.3 – 1.7 billion for the ‘full approach’. This at first appears competitive with some of the other Eastside options, but is only the incremental cost to implement BRT. It is assumed WSDOT will otherwise fund the entire I-405 Master Plan (estimated in 2002 at $10.9 billion total). So we’ll have to see the appetite of the Legislature to make the corresponding WSDOT funding decisions. Other than the 85th St stop in Kirkland, most of the cost difference between A2 and A3 is in Snohomish County, raising obvious questions about how much funding Snohomish would direct to I-405 as it also seeks rail to Everett.
Because WSDOT has built only one HOT lane north of SR 522, and because the highway lacks direct access ramps at key points in this area, the ‘phased build-out’ would see buses run in general-purpose lanes north of Brickyard P&R. Even with two fewer stations than A2, the time penalty for A3 would be five minutes, and there would be reliability issues. Ridership in the phased scenario is about 30% lower than the full build-out. But with costs to Sound Transit alone approximately 50% lower, that might be a reasonable trade-off.
Two service concepts are modelled. One is a single line service running at 10-minute intervals through the entire corridor. Passengers would generally use their own vehicles or local Metro/CT services to reach stations. The other is a ‘trunk-and-branch’ service. This is an overlapping set of four routes, each serving different pairs of communities near the corridor. Headways would be 20 minutes, but combined headways would be as low as 5 minutes between UW Bothell and Renton.
Today’s 405 master plan assumes the single line service model. Sound Transit is concerned a trunk-and-branch model would reduce reliability because their buses would be subject to delay on arterials. But that may be of less concern to riders who would experience those delays anyway. By reaching deeper into communities, Sound Transit estimates it would boost ridership by about 20%.
Depending on the service model chosen, the phased build-out has 14-20,000 riders. The full build-out would see 17-25,000. Against the 800,000 daily journeys on I-405, it’s not quite compelling. But in the context of a master plan that was estimated at $10.9 billion in 2002, and which mostly remains unfunded, some version of this might pass a cost-benefit analysis, at least relative to highway widening projects.