A two-year, $17.1 million reconstruction project covering 2 miles of Trapelo Road and a section of Belmont Street on the Watertown line got underway recently after more than a decade of planning, officials said. The project extends approximately from Waverley Square along Trapelo Road to Arlington Street’s intersection with Belmont Street . The roadway will be smoothed and bicycle lanes will be drawn, and workers will install new traffic lights, sidewalks, and landscaping, according to the state transportation officials. The project will also replace the overhead wires used by MBTA buses. State Department of Transportation representatives said construction will not take place during rush hours — from 7 to 8:30 a.m., and 3:30 to 6 p.m. — to help minimize traffic delays. The tab for the project will be picked up by the state, representatives said. The project rose to the top of the state’s priority list in 2011 after an independent review found it was sorely needed for community development, state Senator Will Brownsberger wrote on his website. The project has been in the works since about 2000, when residents attended the first workshop to help envision what the reconstruction should entail, Brownsberger said. Watertown and Belmont officials worked together to acquire rights of way needed for the project, he said.