B Segment FAQs

What are the B segment alignments being hotly debated right now?
 
Sound Transit's preferred alignment, B2M, would run off I-90 and north along Bellevue Way SE, serve the existing South Bellevue Park & Ride, and continue up 112th Ave SE, where it would serve a station either at SE 8th Street or Main Street and then continue into downtown.
 
A revised version of the City of Bellevue's preferred alignment, B7, would be known as B7-Revised (B7R) and would run east along I-90, serve a new station a third-mile from the existing South Bellevue Park & Ride, continue over a crossing of the Mercer Slough, north up the old Burlington Northern tracks, serve a station at Main Street, and continue into downtown.
 
A map of the alignments is available here.

I've heard that with various improvements B7R could be cheaper than B2M.

The City of Bellevue's Arup study makes definitive conclusions that B7R would be much costlier than B2M. These conclusions were based off of various assumptions informed by the project environment (i.e., WSDOT's I-405 Master Plan, etc.) and those made in Sound Transit's SDEIS. Any changes to these assumptions that would purportedly lower the cost of B7R have not been officially studied nor vetted by either the City of Bellevue or Sound Transit and have not been endorsed by any of these parties. Further study of these elements would require costly conceptual engineering work by an unbiased third-party consulting firm and could not be conducted on a back-of-the-envelope basis.

What are the risks of crossing the Mercer Slough, as B7/B7R does?

There are substantial risks associated with the Slough crossing which should not be downplayed. Very soft clays and peats are found in the soil as deep as 100 feet throughout the Slough. Thus, pile supports for a crossing would need to be drilled at least 120 feet deep. Because of the soft soils and subsequent peat movement, WSDOT has found soil loading to the I-90 bridge structures significant enough to warrant special bridge repairs unique to those structures. Design of the B7/B7R crossing would have to take into account soil loading to the guideway's own supports as well as ensuring the peat movement would not change and potentially increase loads to the existing I-90 bridges. These risks are highly unknown and not easily quantifiable.
 
I’ve heard that the B7R alignment could be optimized with curved platforms at East Main Station. Would this be possible?

While curved stations exist throughout the world and do not typically encounter significant operating or safety issues, such stations would not be appropriate for Sound Transit's light rail system. Curved stations are not ideal for Link light rail because the system’s Kinkisharyo vehicles are configured with exterior-mounted cameras that look down the outside of the train, allowing operators to observe all doors when trains stop at stations.  At these times, operators must be able to see if passengers are still boarding, deboarding, or if some other activity is going on along the platform that may require the operator's attention.  Curved stations eliminate this line-of-sight capability and pose potential safety risks and liability issues that would not occur with straight platforms.  Link light rail’s ADA-compliant level-boarding feature is also contingent on a minimum safe gap between platform and train, which would be optimized with a straight station over a curved station.

Doesn’t the B7/B7R alignment facilitate a future light rail extension further east to Eastgate/Issaquah?

No.  While the placement of the A-2 Station does allow it to be served on a further Eastgate/Issaquah line, the route profile of B7/B7R at the Mercer Slough crossing as currently configured is not feasible for such an extension.  To continue further east, the line would either have to enter a tunnel under the I-405 right-of-way or cross over the freeway in an elevated guideway.  A tunnel would be impractical because of an existing municipal sewer line under the freeway and the Burlington Northern right-of-way that crosses perpendicularly to the line.  An elevated crossing over I-405 would be similarly impractical by requiring a second guideway to be built across the Slough to achieve the necessary climb over the interchange.  This alternative, as conceptually drafted by City of Bellevue staff, would reach a height of 153 feet over 118th Ave SE and 80 feet above the existing I-405/I-90 interchange.

Will B2M negatively impact rider experience with the number of elevation changes in the alignment profile?

While the grade-separation of the B2M alignment requires both depressed and elevated segments, elevation changes along the route will not be any more significant than the parallel roadway profile currently used by Sound Transit’s 550 Express, which experiences a number of sharp turns at Mercer Island and in Downtown Bellevue as well as steep grades due to the I-90 ramps.  On the contrary, because light rail trains will run in dedicated right-of-way, do not have to contend with unpredictable traffic conditions, do not stop outside stations, have fewer sharp turns, and have longer stopping distances than buses, rider experience should improve with the B2M alignment.  Vertical elevation changes along the route profile occur over lengthy horizontal distances and should not negatively impact riders.   

Won’t the A-2 Station and South Bellevue Park & Ride have the same ridership?

While A-2 Station's ridership is comparable to that of the South Bellevue Station, there are key differences in the quality of ridership generated by the two stations.  Travel demand forecast modeling conducted by both Sound Transit and Arup show that the South Bellevue Station generates a greater share and number of person-trips connecting from non-automobile modes in the PM peak period, like walking, bicycling, and bus transit.  Conversely, the A-2 Station attracts a greater share and number of vehicle trips (either kiss-and-ride or park-and-ride) than does the South Bellevue Station because of easier vehicular access to I-90 and the addition of 50 parking spaces over the latter.  

This indicates that South Bellevue Station’s more centralized location has higher usage among riders either living or working withing walking/bicycling proximity of the station.  By serving surrounding neighborhoods more directly, the South Bellevue Station draws fewer long-distance vehicle trips than the A-2 Station which in turn diminishes the net vehicle-miles traveled (VMT) of access/egress vehicle trips generated by the station.

What could be done to improve pedestrian/bicycle access to an A-2 or South Bellevue Station?

Though both stations serve roughly the same commuter park-and-ride market, the distance of the A-2 Station from the South Bellevue Station is significant enough that there are different pedestrian markets served.  South Bellevue’s centralized location can be optimized by adding new pedestrian/bicycle connections to the neighborhood street network that can greatly expand the station's service area (i.e., connections between Bellevue Way SE and cul-de-sac loops in the Enatai neighborhood).  This is not possible with A-2 Station because its location abutting I-90 geographically limits access throughout the ped/bike network and therefore cannot be optimized by similar street network improvements.  A pedestrian/bicycle access point from the I-90 Trail to the A-2 Station platform could improve connections, but this would require the addition of a costly elevator/stairwell.  Furthermore, because Mercer Slough absorbs most of the geographical coverage this access point would provide, only a few properties would benefit.

Which alignment is more prone to gaining ridership in the long-term, B2M or B7/B7R?

Sound Transit ridership models do not consider significant area-specific land use changes that may occur in the future and are instead based on broader regional land use forecasts modeled by the Puget Sound Regional Council.  All stations along the B7/B7R alignment, A-2, 118th, and East Main, are essentially freeway stations that would have diminished geographical service areas and constrained pedestrian/bicycle access.  Because there is better ped/bike access to the South Bellevue and SE 8th/Main Stations, future ridership demand will be more elastic to changes in land use and employment/population densities within walking-distance proximities to the stations.  B7/B7R’s freeway stations, on the other hand, would see long-term ridership more likely to hit a ceiling because a greater share of station usage would be contingent on limited parking capacity.  

Which station will be optimal for riders connecting from buses?

Because the A-2 Station’s transit center and roadway access design requires the configuration of cloverleaf-style ramps and loops, bus transit will be negatively impacted due to increased travel times over what would be expected with the South Bellevue Station.  Riders aboard these buses would experience either a transfer penalty if connecting to light rail or a time penalty if traveling through the station.  Travel demand forecasts indicate there would be 19% fewer person trips connecting from or to bus with the A-2 Station than with the South Bellevue Station.

Will either the A-2 Station or South Bellevue Station increase density in my neighborhood?

While there are concerns of "densification" and changes to neighborhood character because of a future light rail station in neighborhoods like Enatai and Surrey Downs, Sound Transit currently has no legal authority to carry out station-area zoning, which might allow for denser developments to built around light rail stations.  Recent bills in the State Legislature to mandate station-area rezoning have also failed to pass. Thus, zoning authority is currently only reserved under the jurisdiction of local municipalities.  According to the FEIS, there will likely be no land use/zoning changes around South Bellevue stations. Thus, it would be very unlikely that out-of-scale transit-oriented development projects would occur along the B segment in the foreseeable future

Nonetheless, it is imprudent to apply one’s personal and subjective definition of character to the same neighborhoods many years from now.  Future generations should have the flexibility to plan and shape their neighborhoods around the light rail stations as they see fit.  Siting a station outside or in the periphery of the neighborhood revokes this flexibility.

Won’t the B2M route decrease my property values?

While it is impossible to accurately predict how property values along the alignment might change in the long-term, numerous studies conducted nationwide have shown that residential properties within walking proximity to a rail station have experienced positive increases in value over time.  By providing an additional transportation option for neighborhood residents, homes along the B2M route would likely see a net increase in property values, particularly around the South Bellevue and SE 8th/Main Street Stations, which would give easy walking access to the Enatai and Surrey Downs neighborhoods.  On the contrary, homes along the B7/B7R route would be well out of walking distance to proposed stations and would not likely benefit from any economic impact generated by the light rail line.  

I’ve heard that the B2M route requires massive tree removal along Bellevue Way SE and 112th Ave SE.  Is this true?

The B2M route would permanently impact 0.7 acres of high-value habitat in the form of vegetated deciduous forest, which would require the removal of mature trees near the ‘Y’ intersection.  However, the B7 route would permanently impact four times that amount-- 3.0 acres of high-value habitat in the form of high-value coniferous and deciduous forests, as well as the riparian forest buffer zone between the Bellevue Way/I-90 ramps and the Mercer Slough.  Because 0.8 acres of deciduous forest alone would be permanently impacted, more vegetation would actually be removed with the B7 alignment than the B2M alignment.  With the City’s B7-R alignment and A-2 Station, overall ecosystem impacts would increase in the form of greater wetland and buffer impacts.  The station would also require the addition of 4.9 acres of impervious surface, which would necessitate the treatment of polluted stormwater runoff into Mercer Slough.

Furthermore, much of the vegetation removed in the wetland buffer along B2M north of the ‘Y’ intersection would be in the form of noxious and invasive weeds.  Removal and replacement of these with native species following construction could actually improve the function of the wetland buffer.  

*All empirical data is from Sound Transit's Final Environmental Impact Statement for East Link or the City of Bellevue's B7-Revised Study.  Specific citations can be provided upon request.