Build Real BRT for West Seattle

by ROSS BLEAKNEY

[This seems a good a time as any to remind everyone that guest posts do not necessarily reflect the views of STB staff or the editorial board - Ed.]

What exactly is Bus Rapid Transit (or BRT)? Perhaps, like the Supreme Court said about "pornography", you know it when you see it. If the Wikipedia definition of BRT is any guide, I haven't seen it in Seattle. To quote their definition, "To be considered BRT, buses should operate for a significant part of their journey within a fully dedicated right of way (busway) to avoid traffic congestion". RapidRide is not BRT, falling well short by ITDP standards.

But we can certainly build a real BRT system for West Seattle that has almost every advantage of what we call "light rail" (mostly grade separated, off-board fare collection, station platforms level with the bus floor, priority at intersections, etc.). Unlike the light rail concepts being offered by Sound Transit, BRT to West Seattle would allow riders from all the key corridors of West Seattle (California, Fauntleroy, 35th, Admiral/Alki and Delridge) to enjoy a fast and frequent ride to downtown without having to transfer.

The Challenges of Serving West Seattle with Transit

West Seattle is a fairly large area, separated from the rest of Seattle by the Duwamish River. If you look at a census map of West Seattle, there are a few pockets of scattered density, but nothing over 25,000 people per square mile. The more densely populated areas are not in a line, either, making it all but impossible to connect the area with one rail line. A light rail line that serves the Junction is likely to miss Admiral, Alki and the Delridge corridor. A rail line on Delridge would miss Admiral, Alki, California, Fauntleroy and 35th.

Link to West Seattle would be expensive. It would have to traverse low-ridership Sodo and Harbor Island, cross water and rugged terrain. Martin Duke estimated the cost of getting to the junction at $2 - 2.5 billion, not including a downtown tunnel.

The city is unlikely to build parking around the stations, meaning that most riders would walk to the station or arrive by bus. A comparison of population density and the proposed set of stations shows that no set of West Seattle stations will be within walking distance of a majority of potential riders. For light rail to be successful, a vast majority of riders would have to arrive to the station by bus.

Transferring from to bus to train incurs a transfer penalty: exiting the bus, walking to the station, getting to the platform, and waiting for a train (Sound Transit suggests headways of ten minutes). In most of Seattle, the train makes up for that penalty by using its dedicated right of way to outrun buses mired on surface streets. In West Seattle, however, there is easy access to a high-speed freeway if agencies execute several relatively low-cost infrastructure projects. For most riders on West Seattle's major bus corridors, this would result in a faster trip to and through downtown than with light rail.

Maps by Oran Viriyincy

Making it Work

West Seattleites are understandably skeptical about BRT, given their day-to-day experiences with traffic on the bridge. Creating real, reliable BRT would involve more than painting a few buses. It would mean several major investments in our infrastructure capacity:

1) Build the West Side Transit Tunnel (or WSTT) - This is essential for any BRT plan involving West Seattle. The bus routes listed in the diagram serve as a good starting point for future BRT routes (serving dozens of neighborhoods in West Seattle).

2) Build ramps connecting the SoDo busway to the Freeway. This is part of the WSTT plan (as shown on the diagram) but it is worth mentioning.

Existing Bus Lanes on the West Seattle Bridge

3) Improve the bus lane weave on the West Seattle Freeway. The current situation is shown above. The bus lane starts midway over the Duwamish, between West Seattle and Harbor Island. Cars have to cross over the lane if they are getting on the freeway and want to continue past SR 99, or are getting off of the freeway at 99. There is also a bus only lane on the Admiral Way/Avalon Way on ramp, which starts midway into the long ramp. This bus lane does not have to merge with traffic where the other Admiral/Avalon traffic merges, but simply continues on, as another lane is added. Delridge traffic does not have to merge either, as a fourth lane is added there.

Proposed West Seattle Bus Lanes

Two different measures would improve reliability here:

(a) A ramp meter on Delridge (see below) would limit the volume of cars trying to merge into traffic in the path of the bus.

(b) For even greater reliablity, a bus bypass lane further east would go over or under the 99 on-ramp. It would be to the south of the existing ramp (in the far right lane). This means that a driver that wants to go on SR 99 would not get in the far right lane, but get in the lane next to it (second to right). The far right lane would be for buses only (and connect to SoDo). Therefore, buses would only contend with (metered) traffic entering from Delridge. All other traffic would have no reason to enter the bus right-of-way.

4) Add a new bus only lane along the freeway from the current end (at SR 99) to the new ramp to the SoDo busway.

With the vast savings over a completely new rail right-of-way, Sound Transit could easily fund a series of smaller improvements to entrench the BRT time advantage:

5) Add ramp meters for most of the other on ramps to the West Seattle Freeway. This is pretty cheap and is done throughout the city. Basically, this pushes the traffic back onto the streets, and away from the freeway itself. For example, at the Delridge ramp, you would have two lanes - one for HOV and one for SOV. The SOV waits, the HOV doesn't. This allows a bus to jump ahead quite a bit. Traffic is much worse heading out of West Seattle, rather than into it. By adding metered ramps, you reduce the number of cars on the freeway. You also get the buses up to the bus only lanes (without any additional work). This would be controversial. A lot of drivers won't like it, but they should be used to it. I don't think anyone feels that a trip on I-5 is substantially slower because of the metered entrances - they realize they only apply when I-5 is slow (and it doesn't matter where you wait).

6) Convert street parking or general-purpose lanes to HOV on Avalon. HOV conversions are inexpensive at the scale of large capital projects. The city is doing this sort of thing on Aurora and is likely to soon do this on Madison.

7) Convert lanes to HOV on other West Seattle corridors (Delridge, Admiral Way, Fauntleroy). In some cases this will be very difficult or unnecessary, but in many cases, this would be a huge improvement. This sort of improvement often makes a bigger difference to more riders than would the creation of light rail. Not only do you avoid the transfer, but the trip is faster in areas away from the freeway.

8) Add signal priority along all the major routes. There are a few places where this would be tricky, but in many places it looks pretty simple.

9) Divert the 116 to Avalon. If Avalon is fast (as it should be) and getting on the freeway is fast, it really isn't much of a detour. This simplifies the work needed to make all the buses run fast, adds a little connectivity to the BRT system and increases frequency for Avalon bus riders.

Cost

The most expensive part is the WSTT, but a downtown tunnel is common to both light rail and good BRT solutions. The branched configuration of the WSTT might be more expensive than the Link downtown concept, but only to get the additional service advantages.

The next two suggestions are expensive, but nothing compared to any of the plans for light rail to West Seattle. This isn't a huge amount of new freeway, and it is in a fairly cheap construction area. It is not as expensive as dealing with the freeway west of there (which has very high bridges). Recently, the widening of the Spokane Street Viaduct cost $163 million, according to the state report. This proposal might be more expensive, but not a lot more.

The remaining items are fairly cheap. The city of Seattle has already done work identifying some potential improvements as part of the Transit Master Plan.

By my estimation, after you paid for the WSTT (also a part of any light rail proposal), you would have to spend another $250 to $500 million (and I think that is being conservative) to have buses run essentially unimpeded from West Seattle to downtown (and to Queen Anne). That is well over $1 billion less than an inferior light rail alternative.

Conclusion

While some in West Seattle would be better off with light rail, the vast majority of West Seattle riders would be better off with BRT. Riders from all over West Seattle would be able to travel faster and more frequently from their neighborhood to downtown without a laborious and infrequent transfer.