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(Disclaimer: The items expressed here are not an exact science, I have tried to figure out what the current capacity for downtown buses are and have not come up with a decent method to determine that. I have based the over capacity currently on frequent observations on a Friday night when I visit downtown Seattle when I see 522s, 590s, and other buses that should be more spread out jammed together. If I ever figure out how to come to a capacity I will update later.)

Convention Place Station at night
Image from SounderBruce

Starting in 2018

1) The Alaskan Way Viaduct will begin to be torn down, meaning the waterfront is going to be under construction.
2) Work on the City Center Connector will begin, bringing construction to First Avenue and eventually to Stewart Street.
3) Convention Place Station will close and buses will be surfaced from the tunnel, adding more pressure to an overcrowded surface
4) Madison BRT, Rapid Ride G will begin construction.
5) Colman Dock will begin construction for it’s brand new terminal building along with the Alaskan Way Waterfront.

Sequencing large projects is already a challenge, having them all occur at once is bound to create some serious constraints that paint and light re-timing won’t solve. By that time, buses coming from I-90 will be rerouted off the D-2 roadway. Downtown Seattle already has almost 200 buses per hour during the peak of peak and bunching still happens throughout. Once on a Friday evening, I saw 4 590s within 3 blocks of each other on 2nd Avenue. Bus bunching and reliability is already an issue  and with a lack of redundancy, something needs to give way. Out of the decisions to be made, the easiest from the surface view would be to delay the Convention Place station until Northgate Link is ready to run. This would accomplish the following.

1) 41 and 550 continue to run in a reliable right-of-way.
2) Downtown throughput would be maintained given Link is nearing capacity southbound during pm peak at current headways.
3) Layover space for Metro that is becoming a premium in downtown would be maintained.

Right now the surface is constrained having almost 400 buses during the peak hour travelling to and from. While truncating to one end of downtown or the other sounds great, if travelers are suddenly having to transfer to reach their destinations, transit ridership could decrease from adding inconveniences to transit riders.

Here is the current bus numbers for downtown.

Some bus priorities should be implemented regardless

1) 3rd Avenue’s bus only restriction should extend into Belltown at least to Wall Street to keep the E line and other routes moving.
2) 3rd Avenue should be bus only from 6 am-8 pm 7 days per week at a bare minimum.
3) Extend the 2nd Ave and Stewart Ave bus only lane restrictions to 10 am during the morning rush.

Just to measure drawbacks if the 3rd Avenue bus restriction is extended into Belltown, you would lose around 80 on street parking spaces and potential loading or unloading zones if it is an outright restriction.

What do we have now and why do we still need the bus tunnel until at least 2019 if not 2021?

Currently, Link has 2 and 3 car trains running. If we look at 1/3 of trains being 2 car and 2/3 of trains being 3 car at 200 crush load, you come to 5,400 passengers per hour in the tunnel.

The current buses in the tunnel are typically 60 foot artics that can carry 104 people. (source) With as many as 39 buses per hour, that adds up to 4,056 passengers per hour.

If you cut to Link only before you have new cars and more headways, you cut underground throughput by more than 1/3rd let alone deliver unpredictability to current tunnel routes. Based on this, new Link cars would be needed to maintain current through capacity in downtown that will already be curtailed from construction elsewhere from Alaskan Way and 1st Avenue. When the new cars are ready you would be able to increase the capacity in the tunnel to about 6,000 people per hour at current headways crush loaded. If we look at the 2017 SIP for Sound Transit the PM peak shows a bit of an issue getting close to capacity during PM peak. While it sound great to have more filled trains, any breakdown in the system will cause ripple effects. AM peak has more room for more people but PM puts an already delicate system one incident away from disaster.

https://docs.google.com/spreadsheets/d/1pPOTVLoYzjipBSwVCtOFJJx-Mm_ys_nuCm7J8NX80S4/edit?usp=sharing

For Routes 101,102,160, 150 and 255 the inconvenience is put off until later, 550’s misery will be delayed for two years and hopefully East Link will be ready sooner rather than later. 41 would then naturally truncate or simply end. 255 takes up to 23 minutes from Montlake to Downtown during PM peak but most other times it is around 15 minutes or so. By the time you add in the current slogging through to Husky Stadium, transfer penalty, and vertical circulation you could potentially add travel time to many people’s commutes. The Montlake Phase of the SR 520 project will be under construction as well until 2023. Given construction restrictions there, SR 520 truncation is not a good idea at this point in time until bus priority and better transfers can be guaranteed at UW station. In most cases, travel times would increase given the poor transfer environment at UW.

Conjecture and Hypothesis on Layovers
If there is one feature I notice during rush hour in downtown, many buses deadhead during rush hour. If the buses do not layover in downtown, they likely have to travel to somewhere else through traffic choked areas. Truncating might help in this but truncation may end up backfiring from reduced downtown through capacity in the bus tunnel and on the surface. The reduction in one seat rides for peak hour buses may simply lead people to choose driving themselves into downtown to reduce the inconvenience.

I have not seen a decent answer yet as to where will all the buses go that do not layover in IDS and Convention Place? Where do you send buses laying over and do you add to the traffic that is already present in downtown or do we keep the buses closer to their origins?

Forcing the truncation of routes has to come with benefits which the UW truncation requires time for vertical circulation. With the Montlake situation and lack of desirable transfers at Husky Stadium and no prioritization for improvements, this truncation I would strongly advise against. Without dedicated bus lanes or signal priority and quick access to the station, I believe many will simply give up on transit.

Conclusions

  1. We can play a gamble of truncation but my personal bet says it would produce unintended consequences of people simply giving up on transit.
  2. 3rd Avenue should be a transit mall during the main portions of the day from at least 6 am to 8 pm daily. The bus only zone should extend into Belltown specifically Wall Street for all the Aurora Buses coming in and out.

2 Replies to “Convention Place is Still Needed”

  1. I think extending the 3rd Ave bus only zone makes sense. I think that possibly all of 3rd Ave between Broad St and Jackson St could be a bus only zone. There is a big number of bus routes entering from the west end of the Seattle Center campus, such as D Line.

    I also feel like Metro is way too focused on getting people to the Central Business District. This results in a lot of congestion in the CBD by express routes. I think Metro should just have local routes feeding major transit centers, and ultra-frequent Sound Transit buses going from these major transit centers to the CBD. East Link will solve some of these problems, especially for the I-90 routes. Due to the congestion problem, plus many other factors, I agree that Metro should delay the closure of Convention Place Station. They should wait until at least Northgate Link is opened, if not wait even further for East Link.

  2. “hopefully East Link will be ready sooner rather than later”

    East Link is the least likely to be done early because of the unprecedented floating bridge crossing. It will have to traverse expansion joints from the fixed land to the moving bridge, which rises and falls with the water level (within a range maintained by the Ballard Locks). We’ve done it with car lanes but this is the first time with railroad tracks. The rest of East Link can’t come to Seattle until the bridge section is finished.

    There’s the simultaneous issue of possible overcrowding between the U-District and downtown. If East Link is not ready by the time Lynnwood Link opens, it should be possible to run Lynnwood-Intl Dist or Nothgate-Intl Dist trains in the interim. I’m also wondering if a trainset could be taken from south Link to run Northgate-Intl Dist relief runs if necessary. I’m wondering what that would to to south Link’s frequency if even headways are to be maintained.

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