The city has proposed turning Thomas Street in South Lake Union into a pedestrian- and bicycle-friendly "green street." But thanks to major concessions to car traffic, the street may not end up being very "green" at all.

During last night's Seattle Bike Advisory Board meeting, Geoff Wentlandt and Dave LaClergue from the Seattle Department of Planning and Development (DPD) presented conceptual plans for turning Thomas St between Fairview and Western Avenuess into a "green" street. A green street has great potential on Thomas, but because of concessions to the deep-bore tunnel, the current design is problematically car-centric at the expense of bicycles.

Seattle defines a green street as "a street right-of-way that, through a variety of design and operational treatments, gives priority to pedestrian circulation and open space over other transportation uses. ...The purpose of a Green Street is to enhance and expand public open space, and to reinforce desired land use and transportation patterns on appropriate City street rights-of-way."

DPD envisions a walkable pedestrian promenade with lots of sidewalk cafes along the north side of Thomas, separated from the road by planters and trees. That would be a positive transformation from the handful of restaurants and bars there now. And it would help turn that stretch of the Cascade neighborhood into a destination instead of a throughway.

Unfortunately, DPD's current design hands over too much of the road to motorized vehicles to really make it a green street. The plan calls for one travel lane in each direction with a dedicated center turn lane. That configuration only leaves room for a single westbound bike lane. Bicyclists heading east would be expected to go one block north to the busier, four-lane Harrison St.

Obviously, cars still need access to Thomas, but a slower, two-lane road with high-quality bike facilities in both directions is more conducive to a green street than a three-lane road with only one bike lane.

According to Wentlandt, WSDOT is predicting Thomas will feed a significant number of cars to and from the north portal of the SR-99 tunnel. In WSDOT's view, that increased traffic creates the need for a dedicated center turn lane. But with traffic volumes in the tunnel predicted to be as low as 62,000 vehicles per day (about half of the Alaskan Way Viaduct's current volume), and with the faster, four-lane Harrison St. just one block north, it seems unlikely that traffic on Thomas will be heavy enough to warrant sacrificing bike facilities.

If the city removed the center turn lane, there would be room to build a two-way cycletrack on the north side of the street. (Putting bike facilities on the south side of the street is problematic because of a block-long section of streetcar tracks between Terry and Westlake Avenues). A two-way cycletrack would promote relatively slow bicycling that would in turn encourage bicyclists to stop and patronize the restaurants and shops, in the spirit of the envisioned green street. A cycletrack could create issues with turning cars, but slower speeds on a two-lane road, combined with short blocks, would mitigate much of the danger, and a distinct, dedicated bike facility would (hopefully) raise driver awareness.

Beyond its design flaws, the green street proposal raises a larger question about how many concessions the city should make to the deep-bore tunnel. Making bicycle and pedestrians play second fiddle to the multi-billion dollar, transit-free car tunnel is short-sighted and contrary to the city's alternative transportation goals.

The good news is the Thomas St. project is still in the early design stages. There's another public meeting about the project planned for mid-August and construction is still many months away. Nonetheless, it's important to think about the bigger picture of this project to ensure Seattle gets a real, people-centric green street, not a greenwashed throughway for cars.
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