Mercer Island Station, as seen from the north side of I-90. Image from Sound Transit.

When East Link’s Mercer Island Station opens in 2023, it will link the Island with Downtown Seattle, UW, Bellevue and Overlake via frequent, fast and reliable transit. Being located in the median of I-90, the design of the station is straightforward. However, there are two concepts that need Sound Transit’s attention: parking and bus connections.


The current Mercer Island park-and-ride facility consists of a two-level garage located on the north side of I-90 and includes 447 parking spaces. The park-and-ride sees significant demand with the garage regularly being full by 7.30am on weekdays. However, only about half of the current users are island residents; the other half come mainly from the Eastside to take advantage of more buses and access to available parking, which may not as readily available at other park-and-rides in the Eastside. At previous East Link open houses, residents voiced their support in favor of a new park-and-ride facility that prioritizes use by Mercer Islanders.

A solution for Sound Transit is to provide more parking at the Marcer Island Community and Event Center (located at SE 24th St and 84th Ave SE), a quarter-mile from the station. Sound Transit is considering two options for parking, either a three-level garage or a surface lot. The parking garage would cost more, but it would have a much smaller footprint than the surface lot. It would also provide about 25 more parking spaces than the surface options (229 spaces versus 203 or 207 spaces). While the new park-and-ride will be farther from the freeway than the current one, there will be nothing keeping Eastsiders out of the new lot or saving parking spaces past 7.30am.

At the moment, there is no mention of pricing parking from Sound Transit. But, a six-month pilot project was carried out earlier this year at four park-and-rides operated by Sound Transit. The project allowed users, for a fee, to reserve a parking space until 9.30am at which time the space would become open to anyone. This pilot project should be implemented at Mercer Island to guarantee open spaces for later commuters or for Mercer Islanders.

Bus Connections

Instead of wasting hours and hours of bus service by continuing service of I-90 buses (like the ST 554 and the peak expresses) all the way to Downtown Seattle, Sound Transit and King County Metro will truncate them to Mercer Island where current bus riders will be forced transfer to East Link to continue their trip to Seattle. This will save as much 20 minutes per bus. Currently, 117 trips per direction on 9 routes (111, 114, 212, 214, 216, 217, 218, 219, 554) are operated between Mercer Island and Seattle. Together, the savings from these routes at least 78 hours of service each day.

Previous options presented involved the buses moving onto Mercer Island streets, adding dozens and dozens of buses per day to already clogged Mercer Island streets. The options would also have required a long walk from the bus stops to the station, which would have made forced transfers unattractive to bus riders. After receiving mostly negative comments from both bus riders and Mercer Island residents, Sound Transit rethought their options and came up with one that kept most buses off of streets while giving the shortest possible walking distance to bus riders.

MI Bus Transfer

A new transit center would be created on the 80th Ave SE Overpass, and Sound Transit’s Route 554 would both drop off and pick up passengers on the overpass as opposed to deviating off toward the park-and-ride. Transfers would be at the door of the station making it easy and convenient convenient for passengers to transfer under a covered facility protected from the weather. Meanwhile, King County Metro Route 216 would drop off at the station door, but pick up at the current transit center. Routes 204 and the now-defunct Routes 203 and 213 would stay on their current routing.

This is by far the best of the alternatives. It gives riders a very minor delay if buses and trains are being timed correctly, and keeps the buses in a single, concentrated area.

This also gives an opportunity to Sound Transit and King County Metro to completely rethink the network of I-90 peak expresses. King County Metro operates two routes, the 212 and 214, with the main purpose of skipping Mercer Island and gaining a couple minutes over Sound Transit Route 554. These routes could now be absorbed into Route 554. King County Metro Routes 216, 218 and 219 could be combined into one peak-only route, which is here described as the 216. King County Metro Route 217 would keep the same routing east of Mercer Island, with the reverse-peak Route 212 being converted into Route 217. King County Metro Routes 111 and 114 could end at South Bellevue Park and Ride instead of at Mercer Island, avoiding the merge across all lanes of I-90 westbound and taking advantage of the future HOV lanes on Bellevue Way on the eastbound journey. And, King County Metro Routes 114 and 240 could be combined, as at that point they will be very similar to the previously suggested reroute of the 240 (assuming the reroute goes ahead).

This would greatly simplify the inner Eastside bus network by combing the structure of nine routes (previously twelve) to a more reasonable four. The benefit of this is more consistent coverage, stop patterns, and increased headways on common corridors.

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Article Author

Guy is a high school student in Bellevue with a strong desire to become an urban planner. Before moving to Bellevue, he grew up in the Paris metropolitan area where he fell in love with and learned from some of the best rail systems in Europe. Translating his experiences from abroad to Seattle, Guy is now passionate about improving this region's public transit (especially marine-based transportation) and cycling infrastructure. Aside from the technical side of things, Guy also enjoys photography and music.