With three years of planning and coordination behind them, Braintree officials say construction of sidewalks near Ross Elementary School should begin this summer. Braintree’s Safe Routes to Schools grant has been in the Massachusetts Department of Transportation pipeline since 2010, with plans to install $550,000 in sidewalk improvements leading to Ross School. Funding was difficult to come by, however, and the project was put off until 2012. Though state officials hoped to have the project finished by the fall of 2012, approvals from numerous government entities and property owners has slowed things down. “It’s attributable to the number of administrative steps that have to be taken to get this project done,” said Peter Morin, chief of operations and staff for Braintree. The last step was the towns granting of two easements on Tuesday. Morin said officials hopes to have everything installed by the time school resumes in the fall.