The Pearl Harbor Memorial Bridge, commonly referred to as the “Q” bridge, will soon be replaced as part of a larger construction initiative aimed at easing area traffic problems.

The Federal Highway Administration has approved just over $4.7 million in supplementary funding to replace the bridge, which carries Interstate 95 traffic over the Quinnipiac River in southeast New Haven. Made available by an appropriations bill approved by Congress earlier this year, the money will serve to fill financial holes in a $345 million plan to replace the aging causeway. The six-year construction project is slated to begin in late 2004.

Mark Rolfe, the program manager of the I-95 New Haven Harbor Crossing Program, said the current bridge has been deemed functionally obsolete, as the daily traffic flow on the highway has outgrown the structure. An estimated 140,000 vehicles drive on the bridge each day, as opposed to the 40,000 that traversed the river when the bridge opened in 1958.

“This bridge has been bouncing up and down from traffic all these years,” said Brian McGrath, the director of the New Haven Department of Traffic and Parking. “[The bridge] wasn’t going to last another 25 years.”

Instead of rehabilitating the existing structure, the state Department of Transportation has decided to erect an aesthetically pleasing modern crossing that will both relieve the bottleneck and stand as an architectural showpiece.

Though design plans and contractual issues have not been finalized, the new bridge will be of the “extradosed” variety, a hybrid between the traditional deck-supported and cable-stayed designs. Developed in Japan and now found throughout Europe, the new “Q” bridge design will be the first of this type in the United States.

Karyn Gilvarg, the executive director of the City Plan Department, said she approves of the upgrade from unimpressive causeway to signature bridge.

“Let’s have it look like a bridge,” Gilvarg said of the characteristic suspension towers and steel cables of the “extradosed” concept. “Let’s have it be a celebration of crossing the river.”

Rolfe said that the new bridge will sit just south of the “Q” bridge and will feature five lanes in each direction, instead of the three lanes running each way on the current structure. Traffic will continue to flow over the old bridge until half of the new bridge has been built, at which point the traffic will be rerouted.

The bridge replacement is part of the much larger I-95 New Haven Harbor Crossing Program, which is supposed to alleviate the travel problems on the notoriously congested 7.2-mile stretch of highway from interchange 46 in New Haven to exit 54 at in Branford.

“That was the impetus for looking at the whole corridor, the need to do something on the ‘Q’ bridge,” Rolfe said.

At a cost of just over $1 billion, construction crews will undertake six major road-widening projects over the next decade. Rolfe said roughly 88 percent of the funds will be provided by the federal government.

Moving east to west along the shoreline, the first project began this summer in Branford. The future projects, including an eventual reconfiguration of the interchange of Interstates 95 and 91 and Route 34, will begin at staggered start times, planned to have the least effect on the traffic flow in the busy northeast corridor. All construction should be finished by 2011.