For many students, returning to campus by car after spring break can mean hours of traffic and delays on Interstate 95, the nearly 2,000-mile highway stretching from Maine to Florida that links Yale to the outside world. But within the next six years, the headache of getting to New Haven may get some relief.

The Connecticut Department of Transportation (ConnDOT) is in the middle of a massive transportation improvement program to modernize 7.2 miles of the I-95 highway, from Exit 46 in New Haven to Exit 54 in Branford.

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This stretch of highway, built in the 1950s to accommodate about 40,000 vehicles per day, now sees upwards of 140,000, according to the project’s Web site. The project began in 2000 with the construction of the State Street train station and is slated to be completed in November 2016, said Michael Piscitelli, director for the Department of Transportation, Traffic and Parking of the City of New Haven.

After a substantial revision to the schedule and increase of cost estimates in 2007, the plan is now running according to schedule and on budget, he said. Eighty-seven percent of the project is federally funded, and 13 percent is funded by the State of Connecticut.

“It’s one of the most congested corridors in the Northeast, and the crash histories are some of the highest in the nation,” Piscitelli said. “This will help unlock some of the congestion that you see on the Northeast corridor move between Boston and Washington, D.C. So it’s as much a regional improvement as it is local.”

For New Haven, the most significant part of this improvement program is the construction of a new Pearl Harbor Memorial Bridge (often called the “Q-Bridge”), which crosses the New Haven Harbor.

From a traffic perspective, the bridge will expand the roadway from six lanes to 10.

As for symbolic significance, it will be the nation’s first extradosed bridge — one that is supported from above by cables and below by concrete support beams, said John Dunham, a supervising engineer for the project.

In the early stages of the project, a group of traveled to Japan, where extradosed bridges have already been built, to research the type of design, Dunham said.

“They wanted a signature bridge leading into New Haven, so they felt a cable-stayed structure would provide that level of signature,” Dunham said.

Still, in some ways the design is a compromise, he said, because nearby Tweed New Haven Airport prevented designers from building a cable-only bridge, which would have been too tall.

By the end of 2006, no contractors had bid for the bridge project, leading ConnDOT to break the construction into three separate contracts, Dunham said. The first phase of work, building the foundation, is currently about 60 percent finished, ahead of schedule for its slated completion in September 2011, he said. The second contractor began physical work in November, making pores for the towers and making foundations on the east side of the bridge, Dunham said.

This second piece of the project, the bulk of the bridge itself, is scheduled for completion in June 2015. Nevertheless, Dunham explained, around October 2012 the northbound I-95 will start to use a portion of the new Q-Bridge.

With drivers already frustrated by congestion on I-95, ConnDOT could not close down any part of the bridge during construction. Instead, one half of the bridge is built next to the existing bridge so as to limit the impact on the highway, Dunham said.

Still, inevitable street closures and traffic delays can happen during construction, which ConnDOT resolves through e-mails alerts and an online newsletter called “Construction News.”

The city works closely with ConnDOT to ensure that construction is as non-invasive as possible, often performing work at night and establishing short detours, said Piscitelli, the transportation director.

He noted that the only time that traffic in Yale’s central campus might see an impact would be if the Trumbull Street ramp off of I-91 begins to get backed up. DOT is working to keep enough lanes of traffic open so that people do not opt to take Trumbull Street.