Immediately east of the Boston University campus, it crosses into Kenmore Square, which is also the eastern terminus of U.S. Route 20. From Kenmore Sq, Route 2 follows Commonwealth Ave to Arlington St. It circles the Public Garden, using Arlington St to Boylston St to Charles S. Route 2 goes along northbound Route 28 at the intersection of Charles St and Beacon St between Boston Common and the Public Garden. Shortly after, Route 2 ends on U.S. 3 or Route 3 while Route 28 north joins with the southbound of Route 3. The route amalgamates and supersedes various named highways in some cases going back to the pre-automobile era. For example, parts of Route 2 are sometimes known as the Cambridge and Concord Turnpike and the Mohawk Trail. In the early 1920s, Route 2 was known as New England Interstate Route 7 (NE-7), a major road connecting Boston with Troy, New York. NE-7 ran roughly where Route 2A (the original surface alignment of Route 2) does now except near the New York state line. NE-7 used current Massachusetts Route 43, New York State Route 43 and New York State Route 66 to reach Troy. Current Route 2 from Williamstown to Petersburgh was previously numbered as Route 96. Route 2 connected as a highway in its current right-of-way at Alewife Brook Parkway at some point before 1937. An upgraded Route 2 was originally planned to continue as Boston's Northwest Expressway (merging with a re-routed U.S. Route 3 at the Arlington-Lexington or Arlington-Cambridge border) to a junction with Interstate 695, the Inner Beltway, but this, along with the Inner Beltway itself, was cancelled in 1970, accounting for the abrupt narrowing at Alewife. In place of the highway project, the MBTA Red Line was extended from Harvard to Alewife in the 1980s. This major project has been planned since 1999. The intersection had an average of 90 accidents a year. The project was intended to solve the traffic and safety problems that had long occurred at the Crosby's Corner intersection (junction of Route 2 and 2A) in Concord. The project, which was expected to cost $71.9 million, widened Route 2 from Bedford Rd in Lincoln to 300 feet west of Sandy Pond Rd in Concord. The project eliminated the at grade intersection, realigned Route 2, and constructed new entrance and exit ramps along with new service roads next to Route 2.