(photo by WSB contributing photojournalist Christopher Boffoli)

During commutes like this morning, when something goes wrong with The Viaduct or the high bridge, many eastbound West Seattle commuters flock to the low bridge. Just one glitch with that: It sometimes opens for vessel traffic during peak-commute hours. That’s a sore spot for drivers such as WSB’er Jennifer, whose question about the situation was featured here last November. West Seattle-dwelling City Councilmember Tom Rasmussen has been pushing for rush-hour restrictions, especially as traffic-affecting work on the Spokane Street Viaduct section of The Bridge gets closer, and talked to WSB about where this stands:

Right now, the low bridge opens “on demand.” The city Transportation Department notes that vessel traffic has right-of-way over vehicle traffic.

Rasmussen hopes the city and other affected agencies, such as the U.S. Coast Guard, can reach an agreement to keep the low bridge from opening 7-9 am and 4-6 pm on weekdays, unless tide conditions and vessel size combine to require an opening during one of those periods — and there aren’t too many such cases, according to this passage from a city report completed last month, looking at low-bridge openings and related factors during a 3-month period last summer and fall:

There were a total of 598 openings during the study period, of which 68 were peak period openings and of those there were only 17 vessels passing that carry more than 5,000 tons of cargo. Our request would not impede those tide dependent vessel and would allow them to pass without delay during peak periods.

Overall, that report found that the bridge opens an average of 23 times per month during the aforementioned “peak periods” for vehicle traffic, and each opening lasts from 5 to 43 minutes. The report also analyzed how much the delay adds up to, for the eastbound morning commute alone:

The data shows that as vessel traffic increases delay to surface traffic increases. Currently, there is an average of 12 minutes of delay incurred by each vehicle caught on the lower level bridge in each direction. The bridge opens 9 times each month during AM peak; assuming each event is catching approximately 70 eastbound vehicles, over the month there are 630 surface vehicles caught in the delay equating to 126 hours of delay every month to AM peak eastbound surface traffic due to the bridge opening.

In addition to that, the report notes, the high-level bridge then gets the hundreds of cars whose drivers saw the “use high-level bridge when flashing” lights in time to divert. (Note that the low bridge is the only option for bicyclists and pedestrians, who were not measured in this analysis.)

When the report was completed in early February, the city sent it to the USCG as part of a formal request for the bridge-opening restrictions.

So then what happened? Councilmember Rasmussen says the city hasn’t heard back yet, but will seek an official response on the status of the request if there’s no word by the end of this week. This is an issue he’s been working on for a while; his staff says Rasmussen first met with a local Coast Guard official in late 2006 and told SDOT the USCG was willing to discuss the situation, but this apparently languished for some months without followup, aside from a temporary moratorium on AM-peak bridge openings during Freeway Fright ’07 last August.

We’ll let you know what happens next. Meantime, while we were talking with Rasmussen, we asked what he favors as a replacement for the “Central Waterfront” section of The Viaduct that Gov. Gregoire says will come down by 2012, one way or another: “I don’t want to see an elevated structure,” he says. “I would like to see an alternative to get to and from downtown without that — and to address the through-traffic beyond downtown, how we are going to get everyone through there.”

Coincidentally, city councilmembers are scheduled to get a comprehensive update this afternoon on where the planning stands for Viaduct replacement — all sections and related projects, not just the “Central Waterfront.” As of this writing, we’re planning to cover the briefing, since the 99 corridor is such a crucial connection for West Seattle.