Plan for the future of ST4 as you prepare for light rail on SR 99

A map of the Seattle Metro vision map with the pink line on Interstate 99. (Credit: Seattle Metro)

Once in a lifetime chances are just that, once. New York planners did the right thing in 1870 when they launched the subway system, Barcelona did the right thing when Ildefons Cerdà planned the city’s expansion in 1859, and Sound Transit has a chance to get it right with its Sound Transit 3 (ST3) expansion by planning future expansion that encompasses high-capacity transit corridors and high-growth neighborhoods.

Right now, planners, public commentators, board members, and city council members are all wondering where transit lines should go, whether they should be raised, dug, and how high. or depth we should place them. One such debate is over the Green Line, connecting South Lake Union, downtown Seattle, Interbay and Ballard to the regional system.

The Green Line expansion will be dug and run alongside Highway 99, better known as Aurora Avenue in Seattle. This is where we talk about visions of the future, the possibility of doing something cheap, efficient and logical. Like tracing the gridded Eixample of Barcelona or rolling steam car buggies under New York. This is where we should take advantage of this unique opportunity and build the Pink Line Expansion, a proposal to run light rail to Highway 99 as part of the upcoming “ST4” expansion.

A simple off-ramp construction costs little now and protects us from future mess if/when Sound Transit decides to upgrade the RapidRide E line to rail. While we’re digging, we might as well plan for the future, save money, and save ourselves some headaches. (Map source: Seattle Times. Edited by author).

It may seem expensive, wonky, and complicated. But that’s only if Sound Transit doesn’t plan the expansion as part of ST3. If we don’t plan an expansion now, it will be too expensive, disruptive, and technically complicated to do so later. By building an off-ramp for a future Aurora line, Sound Transit can extend the network to Highway 99 without any service interruptions — something the agency likely wants to be safe from recent news. Seattle Transit Blog came up with this in 2018years before the final routing, and still, four years later, Sound Transit still hasn’t added this layout to its plans.

Well, as we said earlier, chances like these only come once.

For a low cost, the construction of the exit ramp for the future expansion of the pink line will open the possibility of enlarge Connecting the light rail to the corridor with the highest public transit usage in the state. Before the pandemic, the Rapid Ride E line carried 18,000 passengers a day, and, during the pandemic and afterwards, with everyone working from home and downtown still at 35% capacity, it still carries more 10,000 passengers per day.

An elevated train track in the middle of Aurora Avenue with bike lanes, bus lanes and a row of trees to the side.
What Aurora Avenue could look like with an elevated light rail. (Credit: Ryan DiRaimio/Seattle Metro)

This corridor is not only an elevated transit corridor, but also a direct corridor, carrying people ranging from white-collar to working-class people and other people who have to perform their daily tasks without a car. Additionally, when combined with other parallel routes that filter over Aurora, ridership in the corridor increases to 30,000 daily riders.

Ideas for an exit ramp for a future Aurora line have been discussed for some time. (Source: Seattle Transit Blog).

Many would say that means Link should have spanned Highway 99 instead of I-5. But this ship sailed. And we should board this one before it leaves the dock. By building the exit tunnel, we are opening up the possibility of moving these thousands of passengers on a train network that reaches the entire region as jobs and mobility patterns change. A small exit ramp provides the ability to do more.

Who knows, after they build this expansion opportunity and connect Aurora Avenue to the Link system, and the ridership and popularity of it increases, maybe the Washington Department of Transportation will hand over their overpromised Tunnel 99 and we will let operate a bullet train or another extension of Link inside?


Ryan DiRaimo is a resident of Aurora Licton-Springs Urban Village and a board member of the ALUV neighborhood group. He works at a downtown architecture firm and seeks to leave a positive urban impact on Seattle and the surrounding metro. He advocates for more housing, safer streets and public transport infrastructure and hopes to one day see a city less dependent on the car.

Jose P. Rogers