Route 29 was initially designated in 1927 to run from downtown Trenton to Newark , following present @-@ day Route 179 and US 202 between Lambertville and Somerville and US 22 between Somerville and Newark . The route between Lambertville and Frenchtown was originally Route 29A . In 1953 , Route 29 was shifted to follow the alignment of Route 29A to avoid the concurrencies with the U.S. Routes . Route 29 between South Warren Street in Trenton and I @-@ 95 in Ewing Township was upgraded to a four @-@ lane highway , with a portion of freeway , in the 1950s and 1960s . In 1995 , the southern freeway part of Route 29 between I @-@ 195 / I @-@ 295 and Route 129 in Hamilton Township was completed . This freeway section was linked to the rest of Route 29 by a tunnel completed in 2002 . A realignment of Route 29 in Lambertville by the 2000s made the route concurrent with the entire length of 0 @.@ 26 @-@ mile @-@ long ( 0 @.@ 42 km ) Route 165 .