Lots of interesting information, including local driving oddities, old highway maps, photos and information on state roads. http://www.schlichtman.org/mahighways/
Directory of branch offices and road test sites for each of the five districts in the state, provided by the Massachusetts Registry of Motor Vehicles. http://www.mass.gov/rmv/branches/
Independent public authority which developes, promotes and manages airports, the seaport and transportation infrastructure in the state. http://www.massport.com/