The city is once again getting planning help from Tufts University graduate students. Last year, four students from Tufts’ School of Urban and Environmental Policy and Planning prepared a preliminary master plan for the city’s Commercial Triangle, 110 acres that border Revere Beach Parkway, MBTA commuter rail tracks, and the Chelsea city line, This year, another four-student team from the school will create a Sustainable Transportation Master Plan for the city, focusing on ways to improve and better connect transportation options for pedestrians, bicyclists, and automobile and public transit users, according to James Errickson, the city’s director of planning and development. In addition to its research and analysis, the Tufts group will also help with community outreach and education. Public meetings will be held during the process. The study will get underway shortly and continue through late April. Errickson said the study will cost the city only about $300 to $400 to cover expenses.