A transit bridge across the Montlake Cut?

Montlake's bascule bridge pictured on Seattle Yacht Club's opening day of boating season (image by author)

The Seattle City Council's Planning Committee recently considered whether to endorse a second bascule bridge serving transit across the Montlake Cut. Current city policy does not favor a bridge for transit unless specific triggers are met. However, changing circumstances in Montlake may warrant a revisit. Although last week's discussion was inconclusive, the question is likely to recur as construction proceeds on SR 520 and WSDOT begins a consultative process with stakeholders in the project later this year or early 2020.

The Legislature funded a second parallel bridge across the Cut in the Connecting Washington package in 2015. WSDOT envisions the bridge being constructed in a third phase of the SR 520 'Rest of the West', but has not released a timetable.

Seattle studied a second bridge in their 2012 deliberations about the SR 520 project and recommended against a second bridge for transit at this time. That position was captured in Council motions in 2012 and 2015. Instead, the City favors an approach whereby Seattle would consider a bridge conditional on certain triggers. Those triggers look to mainline conditions on SR 520, to local level of service for bikes and pedestrians, and to transit speed and reliability on the corridor. Pending those triggers, Seattle would prefer WSDOT direct its funds to other non-motorized improvements.

Should Seattle reconsider its position? Since it's ultimately a state decision, how should the Legislature direct WSDOT to proceed?

Circumstances have changed in several ways since 2012 that appear to improve the case for a second bridge. Most obviously, Metro and Sound Transit have begun routing buses that cross the SR 520 bridge to the UW Link station and are likely to route more buses to UW after East Link opens.

Seattle's earlier deliberation didn't pay much attention to SR 520 buses terminating at UW Link. One should anticipate Eastside cities will pay more attention to the performance of their buses in Montlake in future. Note also that the transit pathway for northbound buses changes next year. Today, buses merge across general purpose lanes just after the bridge to make the turn onto Pacific St. With the North Eastside restructure in March 2020, they will stay on the right to the stops in front of the Link station and use a bus-only left turn signal to turn to Pacific Place. A HOV lane across the Cut that reaches to the station, or nearly, may be more useful now than was anticipated in 2012.

Bikes crossing the bridge mostly share a seven to ten foot sidewalk with pedestrians. That sidewalk is eight to ten inches above the roadway. The curb is the only separation between the sidewalk and the car lanes. Even though conditions for bikes and pedestrians crossing the bridge were already poor in 2012, the Council concluded other improvements elsewhere would be more cost-effective. With the opening of a trail on the SR 520 bridge, bike traffic on Montlake Blvd has grown.

A 2008 WSDOT image of parallel bascule bridges (image: WSDOT)

The resolution recently proposed by Council Member Abel Pacheco would have reversed the City's stance on the bridge, endorsing a second bridge that maintained the same general purpose capacity as the existing bridge and adding one lane in each direction for transit and HOV. The second bridge would also improve and expand non-motorized capacity over today's crowded sidewalks. The resolution failed in Committee; only two members were present and the other, Mike O'Brien, opposes adding lanes. Neither will be returning to Council next year, and indications are scarce what view the future Council might take.

One doesn't know how a second bascule bridge would stand up to analysis under current circumstances. But it deserves more careful consideration than it received at Council last week. An early decision might allow bridge construction to be better coordinated with SR 520 improvements. The bridge is opposed by neighborhood interests on historic grounds, because it removes two homes, and because of arguable traffic concerns.

The Legislature has shown little interest in Seattle's preference to spend the money on multimodal improvements elsewhere. WSDOT did make signal improvements recently on Montlake Blvd to improve bus movements after the temporary bus-only ramp from SR 520 closed. If the money budgeted for Montlake transit lanes is freed up, other cities will press to redirect the funds to their highway projects.

2010 drawing showing one possible traffic configuration on twin Montlake bridges (image: WSDOT)