SDOT plans 4th Ave bike lane connection to Seattle Center, but on the wrong side of the street + How to fix it and reclaim Broad Street

SDOT released an early design concept for connecting the 4th Avenue bike lane from its current terminus at Vine Street in Belltown all the way to Thomas Street via Broad Street, passing directly in front of the Space Needle on the way. Well, sort of.

This bike connection could be a huge deal both for local bike transportation and tourism. When biking northbound on the 4th Ave bike lane, the Space Needle seems to rise from the end of the two-way bike lane. But just a few blocks before arriving at the city's most recognizable icon, the bike lane ends and dumps anyone on a bike into mixed traffic on a four-lane, one-way street. The biking experience goes from comfortable and easy to terrifying in a snap, and suddenly the Space Needle feels very far away.

From Google Street View.

The great news is that SDOT is now planning to not only complete the 4th Ave bike lane connection to the Space Needle and Seattle Center but also link it to the Thomas Street bike lane. However, the early design concept needs some significant revision because it places the bike lane on the wrong side of the street and relies on routing people on bikes and scooters onto busy sidewalks next to one of the city's top tourist attractions. Nobody wants the city to send people biking onto the sidewalk! Stop doing this, SDOT, please!

From the project website.

The project description says it will build a new two-way PBL from Vine St to 5th Ave N and Thomas St via Broad Street," but the design shown does not actually achieve this goal. It stops short of Thomas Street and does not connect the bike lane across the 4th/Broad and Broad/John intersections. It would also require adding an awkward diagonal crossing at 4th and Cedar, which would add unnecessary delay and complication to the route.

Thankfully, there are some great opportunities here for improving the bike lane design and the walking environment while improving traffic flow at the same time. The key is to think bigger about the role of Broad Street, which still suffers from design choices made back when it was a freeway access point even though the old trench it traveled in was removed more than a decade ago. Let's rewind for a moment.

A remnant of a freeway removed 11 years agoBroad Street used to go under Aurora and was the primary route to I-5. The Mercer project removed this connection.

Broad Street used to be a major car transportation route, which is why it is so wide. It used to carry nearly 16,000 vehicles per day between Denny Way and 5th Ave and about 11,000 vehicles per day between Alaskan Way and Denny Way. A ridiculous 1950s roadway trench cut across the neighborhood, severing any chance at walking between South Lake Union and Lower Queen Anne for a generation. It's one of the great traffic engineering crimes of city history, so bad that even the car-centric 2010s Mercer remake project was like, Woah, we gotta remove that car trench." It closed for good in 2014, allowing the city and state to fill in the trench and restore Harrison and Thomas Streets.

In 1956, leaders thought this atrocity was a good idea, in part to get ready for the never-built Bay Freeway on Mercer. Photo: Seattle Municipal Archives.

After the connection northeast of 5th Ave was closed and the trench was filled, traffic predictably plummeted. Traffic is so low now that SDOT did not even bother counting the section between Denny and 5th Ave in the latest citywide traffic count, but the section south of Denny carried only 4,500 vehicles per day, which is nothing for a street near downtown and is half what it carried in 2008. The final traffic measurement on Broad Street before the pandemic found 8,500 vehicles per day between Denny and 5th, which is also about half what it was in 2008.

Despite the dramatic drop in traffic and the removal of the street's freeway connection, the design of Broad Street has mostly remained the same. It still has five lanes, for example, even though its current traffic could easily fit into two (one in each direction). It is still built out like a freeway connector, which is absurd since its current role would be better described as the gateway to the Space Needle. It has a ton of excess space that is crying out to be put to better use. So let's do it!

How to fix Broad Street (and this project)

There are likely many great options, but to get us started I'll suggest one. At the intersection with 5th, there is a support column for the monorail that divides the road into two sections, and it helps form the crux of the solution: Convert Broad Street into a one-way street and reclaim the half of the street width between the monorail column and Seattle Center. SDOT can then create a bikeway adjacent to Seattle Center that is fully separate from the sidewalk as well as plenty of space for charter bus and taxi loading, which is also a stated goal of this project. Every crosswalk on Broad would get dramatically shorter, improving safety and comfort for all the people trying to get to Seattle Center via 5th, 4th or John. The city should probably also reverse the traffic direction of the block of 4th between Broad and Denny, which would make it easier for people in cars to turn eastbound onto Denny Way. They could maybe even keep the angle parking in front of the KOMO building, though a better option would be to widen the sidewalk to carry a larger share of crowds before and after major events since 4th is the simplest walking route between the Space Needle and Westlake Station/downtown.

This design would also allow SDOT to simplify the complicated and inefficient Broad Street/Thomas Street offset intersection at 5th Ave, improving traffic flow on 5th. Streets that move across a grid on a diagonal tend to really screw up traffic signal timings on every street they touch. Since Broad Street no longer serves a major traffic role, traffic flow on actually important traffic streets like 5th could benefit from simplifying Broad Street's intersections. For example, if Broad Street were one-way southwestbound, the city could remove an entire signal cycle currently dedicated to letting people turn left onto 5th Ave N. As it is today, when Broad Street has a green light, nearly every crosswalk and all 5th Ave traffic must wait. That signal time could be instead reallocated to 5th Ave and the Thomas Street crosswalks, improving traffic flow and walkability. Left turns from eastbound Denny Way to Broad Street are already illegal, and the relatively low number of vehicles traveling straight on Broad Street from Belltown to 5th Ave can easily reroute via Cedar Street. The city can also restore the missing crosswalk on the west side of the 4th and Denny intersection.

All of this added together would open up a great opportunity to create an inviting and exciting gateway to the Space Needle loop and fountain at Broad and John. With about half the street space to work with and no awkwardly-turning cars from 4th onto northeastbound Broad, there are opportunities for public art as well as safer sidewalks and crosswalks for folks taking photos or crowds emptying out after a major event. This is the access point closest to downtown, but the freeway remnant that is Broad Street is holding it back.

Additionally, a two-way bike lane on the northwest side of Broad Street also better sets up a future planned protected bike lane on Broad Street all the way to the Elliott Bay Trail and the newly-opened Alaskan Way bikeway. This connection is in the 2024 Seattle Transportation Plan, and a two-way bikeway on the northwest side of the street would likely be the best option for making seamless transitions to Seattle Center and the waterfront routes. If the city builds a bikeway on the southeast side of the street now, then that decision will complicate this future bike project as well, and we'll end up with even more awkward diagonal crossings.

From Broad Street, the bikeway could wrap around the corner onto 5th Ave, where there is already some unused painted buffer space along the curb. With a proper barrier, this would provide a direct and complete connection to Thomas Street. This project could end there, since connecting to Thomas is the stated goal. However, we need to somehow connect the planned Broad Street bike lane to the 5th Ave bike lane stub that currently ends at Republican Street just two blocks north of Thomas. The most difficult section is the block next to MoPop, which is as skinny as the road gets and has a bus stop. However, there is still enough space for a two-way bike lane on the Seattle Center side. Installing an on-street bikeway also allows the city to complete with connection without needing to make a deal with Seattle Public Schools, who own Memorial Stadium and the parking lot between Harrison and Republican and have so far resisted continuing the bikeway through district property. This connection does not absolutely need to be part of the current project, but it will remain a frustrating two-block gap in the bike network.

This project is on a fast track to be completed before the World Cup in summer 2026.