Third Avenue is easily the most important transit corridor in all of Seattle. The street carries more than 52,000 passengers on weekdays via bus. That heavy load of riders translates into transit congestion where hundreds of buses operate along the corridor at peak hours using a complicated “skip stop” approach. A bus will stop every other block on the central portion of the spine even though every block has a bus stop to maximize capacity and throughput. While regionwide transit lowers pollution and climate emissions, concentrating so many routes on Third Avenue does make for localized impacts including pollution and noise.
In May, the Downtown Seattle Association followed up on an earlier visioning phase, releasing more complete options for a redesigned Third Avenue. The Downtown Seattle Association has put forth four divergent long-term concepts showing how the street might function with sidewalks and transit as the focus. Street changes could have impacts to the flow and operation of nearby streets as well. The concepts show where bike lanes and general purpose lanes may go. Additionally, the updated concepts also depict how the pedestrian realm could function on Third Avenue. Underpinning all of this is a storied analysis of peer cities, past planning efforts for Third Avenue, existing conditions, and projected future demand of Downtown streets.
The busiest portion of Third Avenue stretches from Pike Street to Seneca Street where up to 290 buses operate per hour per direction. But the street remains fairly busy from Blanchard Street to James Street where buses converge and peel off of the street. This is depicted well in the image below:
Third Avenue is not just the busiest bus corridor in Seattle; it also happens to stand out as one of the busiest in North America, too. By a hair, Third Avenue edges out Vancouver’s Granville Street in terms of ridership. It does that, however, with a vastly higher number of peak hour bus trips. San Francisco’s Market Street, Denver’s 16th Street Mall, and Minneapolis’ Nicollet Mall also are peers to Third Avenue.
The street design between these differs substantially. Third Avenue currently has four vehicle lanes, which are largely restricted to buses along the core portion of the corridor. The pedestrian environment is somewhat narrow on some portions with sidewalks averaging about 19 feet per side. Vancouver, Minneapolis, and Denver all have smaller roadways for buses (two lanes) and wider average sidewalks (30 feet or more per side).
The Downtown Seattle Association has studied future corridor demand for bus service, which generally indicates that the total number of buses per hour at peak will drop in the downtown core. This is predicated on the fact that transit trips will increasingly convert to light rail as the Link system expands through 2035. A big conversion of trips will occur in 2021 with the opening of the Northgate Link extension with other spurts occurring in 2023, 2024, and 2030 as the East Link, Lynnwood Link, Federal Way Link, and West Seattle Link extensions come on-line.
Looking at a corridor-by-corridor level, the service demand on individual streets in the downtown core varies greatly. First Avenue, for instance, is projected to require the same number of trips today as it will in 2035. Fourth Avenue would see the number of peak-hour trips decline by more than 75% by 2021 while a more measured decline is projected for Second Avenue in the same period. Third Avenue, however, would continue to see increasing numbers of trips through 2021 before slightly declining in 2025. A big drop in peak trips for the corridor would finally come by 2035, which seems to suggest that many express bus trips from West Seattle and Northwest Seattle would be eliminated in favor of light rail.
History of Third Avenue plans
In the vision report, the Downtown Seattle Association goes to great lengths in documenting the history of the Third Avenue corridor. First established in 1853 through platting by famed fathers of the city–Arthur Denny, “Doc” Maynard, and Carson Boren–the corridor rapidly become a hotbed for investment and development. By 1906, streetcar tracks were laid down on Third Avenue. Then in 1911, a major civil engineering plan, known as the “Bogue Plan”, proposed a cut-and-cover transit tunnel under the street. That plan met defeat by voters in March 1912. That was just the start though for grand plans to transform the corridor.
In 1918, a city engineer, R.H. Tompson issued a report that a subway would someday be necessary along the corridor to meet the needs of population and job growth. Another city engineer suggested similarly in 1920. Fast forward to 1990, a transit tunnel under Third Avenue finally opened after decades of unsuccessful efforts to build some sort of underground transit tunnel.
In order to accommodate light rail in the tunnel, buses were “temporarily” moved onto surface streets to Third Avenue in 2005, making it a transit priority street. The surface street remained a primary bus corridor after the tunnel reopened for bus and rail operations. Buses operated in the tunnel until this year when it was finally fully converted to rail-only operations, putting more buses on Third Avenue and nearby streets.
Updated concepts for Third Avenue
The Downtown Seattle Association is still considering four divergent concepts for how Third Avenue could function. These include concepts for a Compact Transitway, Median Transitway, Transit Shuttle and Hub, or Transit Couplet approach. The updated concepts include more details on opportunities and challenges with concepts, how they concepts would work, and how right-of-way on parallel streets might operate.
The Compact Transitway concept would redesign Third Avenue so that the street only has three lanes instead of four. One of the existing lanes could be repurposed for more pedestrian realm amenities such as street trees, expanded bus stop facilities, street-side retail space, and additional street furniture. Bus stops would be adjusted so that no block on Third Avenue has bus stops on opposing sides of the street. With the three-lane configuration, the middle lane would swap back and forth along the corridor to act as a through lane in the same direction as the bus stop lane. This would help buses ready for departure to pass dwelling buses.
Third Avenue would be exclusively for transit whereas Second Avenue and Fourth Avenue would each only have one bus lane, one cycletrack, and two to three general purposes lanes. The Second and Fourth would continue to operate as a couplet with one direction of travel, except for the cycletracks which would be bidirectional.
The Median Transitway concept would also involve reducing Third Avenue from four lanes to three lanes. There would only functionally be two lanes since the corridor would generally have a median every other block for loading and unloading buses. New buses would likely need to be purchased that allowed for left-hand loading and unloading since the median puts stops to the left side under normal operational circumstances. Regular buses could be used if the direction for operation on the street was swapped (i.e., southbound on the east side of the street and northbound on west side of the street). This concept would allow for significant expansion of the pedestrian realm with amenities similar and likely superior to the Compact Transitway concept. Meanwhile, Second Avenue and Fourth Avenue would operate similar to the Compact Transitway concept.
The Transit Shuttle and Hub concept would reduce the roadway in half along Third Avenue with one lane in each direction. A single shuttle bus route would only operate along the corridor approximately ever 90 seconds with stops on every other block. Other bus routes would meet the shuttle bus at end hubs, which is similar to the model used in Denver along the city’s 16th Street Mall. With a significant reduction in lanes, the street could be repurposed for more pedestrian realm amenities and improvements, providing the most amongst the concept alternatives.
The Downtown Seattle Association believes this concept would maximize the potential passenger throughput on the corridor since currently, many buses go empty toward the end of their run on Third Avenue unless through-routed. However, it would introduce a minor time penalty for transfers between buses and eliminate one-seat rides to the downtown core. With this concept, Second Avenue and Fourth Avenue would operate similar to the Compact Transitway concept.
The Transit Couplet concept would be a big departure from the existing Third Avenue paradigm. Both Third Avenue and Second Avenue would form a complete transit couplet. Buses would operate northbound on Third Avenue with buses on the east side of the street and one general purpose lane in the southbound direction on west side of the street. That street would have a lane reduction to help expand the pedestrian realm. Second Avenue would in effect have four lanes with the eastern most continuing as a bidirectional cycletrack, a southbound general purpose lane, and two southbound bus lanes on the western side of the street. Fourth Avenue would consist of three northbound general purpose lanes, essentially fulfilling the couplet for non-transit vehicles, and a bidirectional cycletrack.
For bus operations, this concept would provide a stop at each block and allow for passing, which is helpful if buses breakdown. Bus stops would technically be in pairs with a particular route stopping at every other block even though bus stops would be on each block. The report suggests that this concept would help reduce some of the burden that one street has on carrying most city center bus ridership since it would be split between two streets. The couplet could also have the benefit of providing the highest level of throughput capacity for buses and reduce the issue of weaving.
Existing pedestrian experience
In considering how Third Avenue might functionally be altered, the Downtown Seattle Association took stock of the general existing conditions of the corridor for pedestrians. The goal of the two general conditions was to understand how the streetscape currently performs for pedestrians and what are optimal conditions under existing circumstances.
On blocks where there is no bus stop area, the streetscape generally is 22 feet wide with a walking zone approximately 12 feet wide. The remainder of the space is often split with outdoor seating, vending, planters, and other street furniture. According to analysis from the Downtown Seattle Association, such 12-foot wide walking zones can accommodate around 2,880 pedestrians per hour at peak, but that means very high congestion. Their level-of-service standard model suggests that an ideal hourly flow rate would be 360 or fewer pedestrians per hour passing through the walking zones.
On blocks where there is a bus stop area, the streetscape usually much tighter for through-walking pedestrians. The walking zone ranges from five feet to seven wide while the boarding and waiting zone for buses ranges from 11.5 feet to 15 feet wide. Remaining space for outdoor seating, vending, planters, and other street furniture is generally quite small. Based upon the smaller five-foot wide walking zones, such walking zones can accommodate around 1,200 pedestrians per hour at peak with a very high and impeded density of pedestrians, according to the analysis from the Downtown Seattle Association. Their level-of-service standard model suggests that an ideal hourly flow rate would be 150 or fewer pedestrians per hour passing through the walking zones.
Alternative pedestrian experience
The pedestrian experience could be altered if Third Avenue is redesigned. Predicated on the concepts above, the Downtown Seattle Association has suggested three alternatives of how the pedestrian zone could function on the street.
The first alternative would involve a 27.5-foot wide sidewalk capable of handling about 3,000 pedestrians per hour at peak. The walking zone would be about 12.5 feet wide while 12 to 13 feet would be dedicated to bus waiting and loading areas or other streetscape furniture. An additional four to five feet could be use by local businesses for vending or outdoor cafés. This alternative would be paired with the Compact Transitway or Transit Couplet concepts, which would use three travel lanes.
The second alternative would involve a 33-foot wide sidewalk capable of handling about 3,600 pedestrians per hour at peak. The walking zone would be about 15 feet wide while 14 to 15 feet would be dedicated to bus waiting and loading areas or other streetscape furniture. An additional five to six feet could be use by local businesses for vending or outdoor cafés. This alternative would be paired with the Transit Shuttle and Hub concept, which would use two travel lanes.
The third alternative would involve a 27-foot wide sidewalk and 12-foot wide center median island for passenger waiting and loading. Since the sidewalk would be separated from the bus island, it would be capable of handling about 3,600 pedestrians per hour at peak. The walking zone would be about 15 to 16 feet wide while the bus island would be 12 feet wide. The sidewalk would also accommodate five to six feet for streetscape furniture and an additional six feet for use by local businesses for vending or outdoor cafés. This alternative would be paired with the Median Transitway concept, which would use two travel lanes.
The future is uncharted
While there is no active program to fully overhaul Third Avenue right now, there are overlapping programs and planning efforts that local agencies are engaging in where the analysis from the Downtown Seattle Association could be useful. Laying out a longer-term vision for consensus on what Third Avenue could become may be instrumental in getting the buy-in needed to do a bigger revamp on the scale of Granville Street in Vancouver or 16th Street Mall in Denver, both of which are much more vibrant bus spines and active outdoor pedestrian malls. Smaller activation efforts with individual property owners and businesses as well as Downtown Seattle Association-sponsored initiatives may prove to be early wins, but could Third Avenue be fully renewed by 2030? Time will tell.
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