Long-awaited and longer-needed improvements to Dorchester Avenue will begin as early as this fall, thanks to the federal government’s plan to stimulate infrastructure projects across the nation. The $16.47 million road project will be funded in total by the Federal American Recovery and Reinvestment Act championed by President Barack Obama and passed by Congress earlier this year.

The plan calls for “streetscape” improvements along Dorchester’s main boulevard, a revamping of roads, intersections and equipment that is expected to alleviate traffic congestion along the busy two-lane corridor.

“The good news is that the project has been advertised for bids,” said Boston Transportation Department Commissioner Thomas Tinlin, who added that the city will pay an additional $900,000 to purchase trees, landscaping improvements, and other cosmetic features not covered under the strict language of the federal stimulus funding, which is mandated by law to be put only to “shovel-ready” infrastructure projects. Tinlin said that construction is expected to begin in the late fall or early winter and could be completed as early as 2012.

“We’ve never had a handover like this,” said City Councillor Maureen Feeney of the unprecedented funds provided by the federal government’s efforts to revitalize the nation’s struggling economy. Feeney added that Mayor Menino is “committed to dramatic change to Dorchester Ave.,” and that after years of debate and planning, she is excited about the project. “We’re just happy that at long last our wonderful Dorchester Ave. project is happening,” she said.

The massive undertaking will begin near the Ashmont MBTA station and move north before terminating at the intersection of Dorchester Avenue and Old Colony Ave. in South Boston. According to an advertisement seeking bids from contractors interested in the job, the intersections at Peabody Square, Glover’s Corner, Fields Corner, and Andrew Square will be improved for safety and mobility. Traffic signal equipment will be upgraded at these and eleven other signalized intersections along the four-mile route and the stoplights will be integrated into the Boston Traffic Management Center’s system.

Another major component of the project will be the rehabilitation of a sub-surface bridge used by the MBTA’s Redline at Peabody Square.

Although the project was originally planned as a city venture, the use of federal stimulus funds required that the project be moved to the control of the Massachusetts Highway Department. Mass. Highway released the advertisement soliciting bids last Saturday. Contractors are typically given three to four weeks to respond, Tinlin said, before a contract is awarded. Once the bid package is accepted and the contract is awarded, state highway officials and the contractor will work out a schedule for the project.

Handing a completed plan over to the state and relinquishing control of the project is always unsettling, Councillor Feeney said, but she is confident that a collaborative effort between city and state officials will be successful.

Having the entirety of the funds in place before a shovel has even hit dirt will let officials and the contractors schedule the work more easily than other projects, Tinlan said. A full timeline of construction, he said, will “allow [workers] to look at it as it should be looked at, as one corridor,”

The project is expected to bring a total of 150 jobs to the city.

The three-year planning process for the Avenue reconstruction resulted in a plan to build a new Dorchester Avenue that will try to better reflect the community and residents that use the neighborhood’s main street. According to Tinlan, the new roadway will be a part of Menino’s effort to create an “all users” environment, one that is safe and effective for motorists, pedestrians, and cyclists.