In September 2007, the Downtown Seattle Transit Tunnel (DSTT) will reopen for use by bus after two years of closure.

As Seattle's light rail system, which will also travel through the same tunnel, nears it's completion date in late 2009, some view its unveiling with apprehension rather than anticipation.

On Sept. 24, 2005, the DSTT closed up shop for an extensive retrofitting process that will ultimately span four years. The project has been on schedule.

The construction will not only outfit the tunnel for the use of quieter and more eco-friendly, diesel-electric buses which operate wirelessly within it, but it will make way for Seattle's newest mode of transportation: the light rail system that will link Sea-Tac Airport and downtown, as well as branching out to other urban centers including the U-District and Capitol Hill.

"For the first time Seattleites will be able to ride a light rail from Sea-Tac to downtown and all points in between — a fast and reliable way to get to school," Lee Somerstein, Sound Transit's spokesperson, said.

According to the DSTT Web site, the downtown area will undergo an influx of new jobs and households in the next 20 years, making the increase in accessibility to downtown a necessity: 57,000 new jobs and 24,000 new households by 2024.

The city has also invested $16 million into surface road improvements and traffic alterations to help rein in the added congestion that the closure of the tunnel has created during this transitional period.

"We've made 3rd Ave. a bus mall during peak hours," said Stephanie Kirby, construction manager of the DSTT retrofitting process. "We've done this to alleviate any sort of inconvenience to bus passengers during this transitional period."

Some don't view the end of the construction process optimistically, however.

Dick Nelson, principal researcher for Integrated Transport Research, Inc., who headed a 2001 study criticizing construction of the light rail, has many fears about the upcoming system.

"The key issue here is safety," Nelson said. "When you're putting comparatively low mass vehicles such as buses into a tunnel with comparatively high mass vehicles like a light rail train, you have a potential for catastrophic collisions."

Although the access to the tunnel by train and bus will alternate to avoid a wreck such as this, Nelson said this might not be enough.

"Both buses and trains must be synchronized," Nelson said. "But human error is a factor which can't be eliminated. In some cases drivers make mistakes and accidents can happen."

Nelson stresses another potential problem: fire.

"The buses will be carrying large amounts of extremely flammable fuel," Nelson said. "The trains, on the other hand, are run through electricity. Any sort of leak or spill could easily result in fire, and many places along the tunnel open into shops; a perfect outlet for smoke."

Several other factors, such as a suspicious design method where buses actually have to turn over the tracks to return to the other end of the tunnel, lead Nelson and his team to question the safety of such a system in Seattle.

Another concern is the fact that worldwide, light rail safety records are not the best.

"These are important issues which we feel were not addressed," Nelson said.

Somerstein has faith that voters made the right choice in giving the go-ahead for the light rail.

"Our board members ultimately in charge of the project are officials who were elected in 1996 when the project was set into motion by the voters," he said. "By them choosing the light rail as their preferred method of transportation ... speaks volumes for the project."

Time will tell whether Seattle's transition to a new form of transportation goes smoothly.

"Once they start operating," Nelson said, "we'll see how it goes."

Reach reporter Camden Swita at news@thedaily.washington.edu.