The 6/20/14 post detailed how Sound Transit’s delays in adding the 4th lane to the I-90 bridge outer roadways had already forced thousands of cross-lake commuters from both sides of the lake to needlessly endure years of increased congestion. Whatever the reason, their current plans to extend the delay until 2017 will allow ST to never “consider” two-way, bus-only lanes on the center roadway or to “demonstrate” the added lane will provide needed capacity until it is too late to do anything about it. (A 2004 FHWA study concluded center roadway closure will increase congestion on the outer bridge roadways even with the added lane.)
Sound Transit may have believed the increased capacity from light rail will attract enough additional riders to reduce outer roadway vehicle congestion. They were undoubtedly aware of the very successful Bay Area Rapid Transit (BART) system between San Francisco and the Oakland area. It currently averages nearly 400,000 riders every weekday. However it does so with up to sixteen 10-car trains an hour. The Seattle tunnel will limit East Link to 4-car trains every 8 minutes or 7 1/2 per hour (4500 riders per hour (RPH) assuming 150 riders in each of the 74-seat cars).
Furthermore, BART provides easy access to a huge population base with five separate lines serving a wide area on the Oakland side. East Link will be a single line with the South Bellevue and Mercer Island light rail stations the only access for the vast majority of cross-lake commuters. Thus, East Link will do absolutely nothing to alleviate I-90 or 405 congestion, even if it had the needed capacity. To put it mildly “East Link is no BART”!
Yet Sound Transit’s 2008 DEIS claimed East Link would “meet growing transit and mobility demands by increasing person-moving capacity across Lake Washington on I-90 by up to 60 percent.” They supported this assessment with claims light rail could accommodate “up to 24,000 riders per hour” (RPH) and was “the equivalent of 10 lanes of freeway”.
ST projected East Link would have 50,000 daily riders by 2030. More recently they explained 40,000 of the riders would be the result of terminating all existing cross-lake bus routes at South Bellevue and Mercer Island light rail stations. Transferring transit riders from buses to light rail cars does very little to increase cross-lake capacity. Thus it’s “unclear” how East Link could increase I-90 transit capacity by 60%.
Even this limited number of riders is beyond East Link capacity, at least during normal commute hours. The 40,000 total rides are presumably split between 20,000 morning and afternoon commuters into and out of Seattle. With a maximum capacity of 4500 RPH, it will take nearly 4 ½ hours for East Link to accommodate the 20,000 inbound and outbound commuters each weekday. As a result rather than attracting the thousands of additional transit riders needed for their 60% growth projections, East Link will reduce transit capacity. During the peak commute thousands of former bus riders will be forced onto the I-90 outer roadways adding to the congestion there.
By the time East Link begins operation (2023?), I-90 commuters will have had to endure 6-7 years of increased congestion due to ST confiscation of the center roadway. Imagine their outrage when they experience the additional congestion from thousands of former transit riders forced onto outer roadway when East Link begins operation by terminating cross-lake bus routes.
A debacle by anyone’s standards!