I-290 counterpart until it reaches I-495 in Marlborough. Service plazas In Connecticut, there are three service plazas (a legacy of the turnpike) that provide 24-hour gas stations, convenience stores, plus a Subway and Dunkin' Donuts. Montville (milepost 8): It is southbound only between exits 9 and 6. Plainfield (milepost 35): It is northbound and southbound between exits 32 and 35. The Connecticut State Police Troop E barracks occupies the former service plaza on the northbound side at Montville. History The highway that is now I-395 from its southern terminus with I-95 in East Lyme to exit 35 in Plainfield opened on January 2, 1958, as part of the Connecticut Turnpike from Greenwich at the New York state line to Killingly at the Rhode Island state line. In 1964, work began on a freeway extension beyond the turnpike in Plainfield north toward Worcester, connecting to the Massachusetts Turnpike (I-90). This new freeway, as well as the existing section of the Connecticut Turnpike from East Lyme to Plainfield, would be designated as Connecticut Route 52. The section between Plainfield and US 44 near Putnam opened in 1967, and the section from US 44 to the Massachusetts state line opened in 1969. Massachusetts completed its section of the freeway in 1977. In 1983, in response to the cancelation of the proposed I-84 extension from Hartford to Providence, CTDOT wished to supplement the state's loss of Interstate mileage by applying an Interstate designation to Connecticut Route 52. Initially, I-290 was to be extended from its southern terminus in Auburn, Massachusetts. However, in 1983, it was decided to instead apply the I-395 designation to the freeway south of I-90. In May 2013, CTDOT announced that a project that would begin in early 2014 that included renumbering exits along its section of I-395, and Connecticut Route 2A from the then-current sequential numbering system to a distance-based scheme to conform with federal exit numbering standards. During the transition, old exit numbers were posted atop the new exit numbers through 2017 to lessen any confusion. The renumbering began on June 24, 2015, and ended in January 2016; the project included renumbering one sign in Massachusetts announcing the first southbound Connecticut exit. Exit list Exit numbers were changed from sequential to distance-based numbering in Connecticut between July and December 2015. Along with Connecticut Route 2A, these are Connecticut's initial distance-based exit numbers. MassDOT also planned to switch exit numbers