To the delight of commuters across the city and the state, the long-awaited Q Bridge is complete — and eight months ahead of schedule to boot.

A dedication ceremony on Saturday marked the conclusion of construction on the bridge, a major state-backed project designed to ease traffic into and out of the Elm City. The project, which began in 2008 under then-Gov. Jodi Rell, refurbishes the Pearl Harbor Memorial Bridge, adding new southbound lanes. Together with new northbound lanes completed in 2012, the improved traffic arteries will reduce congestion for commuters who cross the Quinnipiac River every day and boost the region’s economy, according to city, state and federal officials.

“This is big — for residents, for the Greater New Haven region and for Connecticut,” Gov. Dannel Malloy said in a statement. “If we want to grow jobs, attract new businesses and improve quality-of-life in our state, then transforming our transportation system has to be a priority.”

Malloy, who has made transportation a priority during his second term, recently proposed an overhaul of the state’s transportation system — in the form of a “transportation lockbox” that protects funds designated for transportation.

Although legislators blocked Malloy’s lockbox plan in July, the Q Bridge is part of the state’s most ambitious and expensive transportation project in recent years. The New Haven Harbor Crossing Corridor Improvement Program — the broader, 18-year, $2 billion infrastructure improvement project — also aims to add lanes and rebuild junctions on Interstate 95 in New Haven and towns along the shoreline to the east.

The new Q Bridge has five lanes and two full shoulders in each direction and can handle up to 140,000 cars a day. Originally intended to carry 40,000 cars each day when it was built in 1958, the old bridge was carrying roughly 120,000 vehicles prior to construction, creating frequent traffic bottlenecks. Additionally, the previous bridge was not fit to withstand an earthquake, city officials have said.

The bridge’s unique design — a hybrid of short concrete towers and cable suspension called “extradoses” — permits airplanes flying in and out of Tweed Airport to pass over the bridge safely. The architectural style of the bridge, used widely in Japan, is the first of its kind in the United States, said Doug Hausladen ’04, the city’s transit chief, who added that the bridge has a century-long lifespan.

The construction of the bridge was largely financed by the federal government, which is paying for 87 percent of the project. State and federal legislators said the project demonstrates the power of cooperation among different levels of government in achieving infrastructure goals.

“This new bridge is a testament to federal and state collaboration — and shared commitment to investment in our transportation systems,” Sen. Richard Blumenthal LAW ’73 said in a statement.

But building the bridge was also a local endeavor that city leaders said will significantly impact New Haven — a city responsible for much of the region’s job growth, according to Hausladen. In the last 10 years, the city’s job base has grown by 11 percent, while the region saw a 4 percent decrease, he added. Hausladen said these numbers underscore the importance of easing commutes into the city.

New Haven, with a small airport, a deep-water port and an expanding railway line, is a transportation hub, Hausladen said, emphasizing the Q Bridge reconstruction’s importance to the region. When New Haven’s major throughways are under construction for so long, the local economy can suffer, Hausladen said. But he added that the construction proved not to be a problem and the city instead saw job growth, not stagnation.

The Q Bridge’s reconstruction is only one of many infrastructure projects in progress across Connecticut. The state is currently working on updating the rail lines connecting New Haven and Springfield, Massachusetts — a project that involves repairing 35 bridges and laying 27 miles of new track with the hope of eventually running 25 round-trip trains daily between the cities.

“Infrastructure is a defining competitive advantage of New Haven,” Hausladen said. “We’re going to be able to maintain this bridge for generations to come.”