More congestion? It depends on who's talking

In 2010 — after the downtown Seattle bus tunnel reopens, after Sound Transit's light-rail trains join buses in the tube — will downtown traffic congestion be worse than it was before the tunnel closed?

That's what some Sound Transit critics contend. Sound Transit and Metro say they're wrong. It's one of the most fundamental differences between the two camps.

In a report last July to light-rail critic Maggi Famia, a Metropolitan King County councilwoman at the time, transportation consultants John Niles, Jim McIsaac and Dick Nelson concluded that, even with 120 afternoon peak-hour buses back in the tunnel in 2010, the number of surface buses downtown during that hour would top 600 — 30 percent more than today.

In a report a month later, Sound Transit and Metro argued buses wouldn't clog downtown streets. The agencies calculated that after the tunnel reopened, afternoon peak-hour surface-bus volumes would return to 460 or 470, about the same as today.

How do the two sides arrive at such different conclusions? By making different assumptions.

Metro assumes slightly less than 1 percent annual growth in transit use downtown, or about five additional peak-hour buses each year. But it also assumes that 29 buses connecting downtown with South King, Pierce and Snohomish counties will be replaced by Sound Transit's Sounder commuter rail as it expands, and that 15 local Seattle buses will be supplanted by light rail.

Those reductions would cancel out the anticipated growth.

Niles, McIsaac and Nelson — all light-rail critics — also allow for such reductions. But they assume much more growth in downtown transit use: 2.4 percent a year starting in 1999, or 14 to 19 peak-hour buses added annually.

The consultants point to projections that downtown employment is expected to increase 20 percent between 1998 and 2010, downtown residents by more than 90 percent. More buses will be needed to keep downtown moving, they contend.

"If they cap (bus) growth at 1 percent, what is that saying about service?" says Niles, technical coordinator for the anti-light-rail coalition Sane Transit.

But the 2.4 percent annual growth he and his colleagues forecast beginning in 1999 hasn't materialized. Metro says the number of buses downtown has declined over the past three years, largely due to consolidations and cuts resulting from anti-tax Initiative 695.

A 1 percent growth rate follows precedent, Metro service planner Matt Shelden says: Between 1986 and 2001, as downtown employment and population grew dramatically, the number of afternoon, north-south peak-hour buses increased at an annual rate of less than 1 percent, from 548 to 592.

Until last year, Metro was forecasting annual growth in downtown bus numbers much closer to what the critics project now. McIsaac says the change was politically motivated.

But Shelden says the old forecasts didn't account for growth since 1986. And they were prepared before I-695 and the recession trimmed Metro's revenues.

Metro's assumption that commuter rail will replace some downtown buses could be risky. Sounder now runs just four trains daily between Tacoma and Seattle; in forecasting bus volumes, Metro assumes 18 trains daily there in 2005. It also assumes Sounder service to Everett would be up to 12 trains daily.

But Sounder's expansion has been behind schedule; King and Snohomish county executives acknowledged this month that Sound Transit doesn't have the money now to expand rail to Everett.

If Sounder does expand, Metro's assumption that it would replace 29 afternoon downtown buses might prove optimistic.

Metro's total includes five Community Transit buses, but CT says it doesn't intend to trim buses when Sounder reaches Everett. The total also includes 12 Sound Transit express buses to Tacoma, but Sound Transit says it hasn't decided to eliminate those trips.