Wikipedia:WikiProject U.S. Roads/New Jersey/Selected article/November 2009

Route 31 is a state highway in New Jersey, United States. It runs 48.93 mi (78.75 km) from U.S. Route 206 (also signed as U.S. Route 1 Business) in Trenton, Mercer County north to an intersection with U.S. Route 46 in Buttzville in White Township, Warren County. Along the way, Route 31 heads through the communities of Flemington, Clinton and Washington. Most of the highway is state-maintained; however, the section within the city limits of Trenton is maintained by Mercer County. Much of Route 31 is a two-lane highway that passes through farmland, woodland, and mountainous areas. Two portions of the route—from Trenton to Pennington and from Ringoes to Clinton—consist of more development.

The highway was constructed from 1926 to 1935. Route 31 has carried two different numbers in the past. It was known as Route 30 between 1927 and 1953, when it was renumbered to Route 69 to avoid conflicting with U.S. Route 30 in southern New Jersey. It was renumbered to Route 31 in 1967 due to sign theft that resulted from the sexual meaning of the number 69. There were plans made in the late 1960s and early 1970s to build a freeway in the Route 31 corridor that would begin in the Trenton area and extend as far north as Interstate 84 in Port Jervis, New York; however, it was canceled in the mid-1970s due to opposition from area residents and environmental and financial constraints. In recent years, the portion of Route 31 between Flemington and Clinton has been widened to four lanes. In addition, there was a failed project to build a bypass of Flemington that would have also eliminated the Flemington Circle.