Big Dig won't quite be ready in 2004

When members of the Democratic National Committee came to Boston last June to hear the city's pitch for the convention, one question was asked time and again: Will the Big Dig be done?

And each time, Central Artery and city officials assured them it would. Even the introduction of the city's official convention proposal touts the project's completion.

"By the summer of 2004, more than 245,000 vehicles now using the elevated I-93 highway ... will be traveling through two 8- to 10-lane tunnels below the city," it reads.

But based on official estimates, that pledge will be impossible to keep. The most that will be open will be a total of six lanes of underground highway by the time the Democrats arrive, according to Central Artery timelines, a fact acknowledged by Big Dig officials.

In fact, renovations planned for the Dewey Square Tunnel under South Station in July 2004 could make traveling in some sections of downtown far worse than it is now, with only two southbound lanes open on Interstate 93. The tunnel currently operates with three lanes.

Also, two on-ramps that now feed into the tunnel from Congress and Purchase streets will be closed during the construction, increasing Surface Artery traffic and forcing cars and trucks to traverse six, often-clogged blocks around South Station and Chinatown.

That traffic will not be able to merge onto southbound I-93 until Kneeland Street, raising the possibility of nightmarish traffic -- even by Boston standards. Still, city and state transportation officials said they were confident that delegates, journalists, and visitors would be able to get around with relatively few headaches.

"The Big Dig will be buttoned up for the most part," Mayor Thomas M. Menino said yesterday. "The roads will be passable."

The city's convention proposal also says that the old elevated Central Artery will be fully dismantled by convention time. That's not quite true. Even Turnpike Commissioner Matthew Amorello said Tuesday that the span would not be fully torn down. In fact, Amorello said he plans to make portions of the elevated line near the FleetCenter available to park media satellite trucks.

Based on the Big Dig's Sept. 30 schedule, the limited-lane access on I-93 south in the Dewey Square Tunnel is expected to be ready around December 2003, in time for the convention. But full access underground to I-93 southbound isn't scheduled to occur until November 2004, three months afterward.

Still, the efficiency of Boston's transportation system was a key selling point in the city's winning proposal, with city officials offering a host of parking and transit perks, including 5,000 off-street parking spots exclusively for conventioneers. Other promised transit amenities include:

• Street closures around the FleetCenter -- the convention site -- including Nashua, Friend, Canal, and Portland streets, with additional nearby vacant areas set aside for parking.

• Free seven-day MBTA passes to the 5,000-plus delegates.

• The promise of as many as 125 air-conditioned T buses available to conventioneers before, during, and after the event.

Despite potential traffic glitches, Boston -- which has handled much larger crowds, such as 8 million visitors in 2000 for the 11-day Tall Ships extravaganza -- will also be much more efficient in moving people in 2004. Among the transportation projects that will be done or close to being done:

• The MBTA's Transitway linking South Station with South Boston under the Fort Point Channel is scheduled to be open by July 2004.

• The renovation of Logan Airport's international terminal will be finished, and the airport's massive $87 million roadway project will be at or near completion. Latest estimated completion date: Aug. 20, 2004.

• The T's Superstation, where the Green and Orange lines will meet on a single platform inside North Station, is scheduled to be ready by July 2004. The project includes an underground tunnel linking the station to the FleetCenter.

• By the end of the year, the Massachusetts Turnpike (I-90) spur to Logan Airport and the new underground I-93 northbound lanes are scheduled to open.

Globe staff writers Glen Johnson and Thomas C. Palmer Jr. contributed to this report.