What is now US 1 between Trenton and New Brunswick was originally chartered as the
Trenton and New Brunswick Turnpike in 1803. Throughout its history, the Trenton and New Brunswick Turnpike faced stiff competition from canals such as the D&R Canal and railroads such as the
Camden and Amboy Railroad. In the later part of the 19th century, the turnpike company folded and the
Pennsylvania Railroad took over ownership of the turnpike. When the charter for the Trenton and New Brunswick Turnpike expired in 1903, it became a public road. When the first numbered highways were legislated in New Jersey in 1916, the present day US 1 between New Brunswick and Elizabeth was to become a part of
Route 1, a route that was to connect Trenton and Elizabeth. Between Trenton and New Brunswick, this route was to follow present-day Route 33 and US 130. In 1922, an extension of Route 1 was legislated to continue north from Elizabeth to the
Holland Tunnel in Jersey City. When the
U.S. Highway System was established in 1926, the routing of US 1 in New Jersey was to follow the
Lincoln Highway from the
Lower Trenton Bridge in Trenton to Newark, which was
Route 13 between Trenton and New Brunswick and Route 1 north of there. From Newark, the route followed present-day US 1/9 Truck east toward Jersey City, where it was to head to the Holland Tunnel. The Lincoln Highway the first transcontinental highway in the U.S. created in 1913 to link New York City to
San Francisco. Route 13 had been legislated along the Trenton to New Brunswick portion in 1917. In the
1927 New Jersey state highway renumbering, the alignment of US 1 between Trenton and Newark became
Route 27, while the proposed Route 1 Extension became part of
Route 25. In addition, Route 26 was designated along the former Trenton and New Brunswick Turnpike, while the current US 1 between Route 26 and US 130 became Route S26. North of current US 130, present-day US 1 to Newark also became a part of Route 25. The current US 1/9 between the Tonnele Circle and the George Washington Bridge meanwhile became parts of
Route 1 and
Route 6. The Route 1 Extension, now designated Route 25, was complete in 1928 with the exception of the Pulaski Skyway. This road was considered the first superhighway in the U.S. After the Pulaski Skyway opened in 1932, US 1 along with US 9 was rerouted to use it. By the 1930s, US 1 was routed to use Route 26, Route S26, and Route 25 between Trenton and Newark instead of Route 27. US 1 and US 9 were routed to use the George Washington Bridge over the Hudson River instead of the Holland Tunnel by the 1940s, following Route 1 and US 46/Route 6 between the Tonnele Circle and the George Washington Bridge. In the
1953 New Jersey state highway renumbering that followed a month later, all the state highways running concurrent with US 1 were removed. In addition, US 1/9 Truck was designated as a bypass of the Pulaski Skyway (replacing
Route 25T) and
US 1/9 Bus. (now Route 139) was designated on the former Route 25 between the Tonnele Circle and the Holland Tunnel. Also, after the US 1 designation was moved to the Trenton Freeway, the former route through Trenton would become
US 1 Alt. During the development of the
Interstate Highway System, New Jersey and Pennsylvania considered having I-95 cross over the Trenton–Morrisville Toll Bridge and continue north on the existing US 1. The project was opposed due to inadequate highway standards (lack of shoulder ramps, and only two lanes in each direction). During this time, both states sought alternate routes for the proposed I-95. In 1960, New Jersey and Pennsylvania decided to designate the
Scudder Falls Bridge as I-95. By 1969, an extension of the Trenton Freeway from the current left-hand exit to US 1 Bus./US 206 to Whitehead Road was completed and received the Route 174 designation. In 1967,
NJDOT recommended an extension of the Trenton Freeway from Whitehead Road to the traffic light at Bakers Basin Road and Franklin Corner Road. Once the extension was completed by the 1980s, the route number was then changed from Route 174 to US 1. The former alignment of US 1 along surface streets in Trenton was renumbered to US 1 Bus., while the US 1 Alt. designation was dropped. There had been plans to create a west–east spur of the New Jersey Turnpike called
Route 92. It was to begin just north of the intersection of Ridge Road and US 1 in South Brunswick and terminate at the mainline of the New Jersey Turnpike (I-95) at exit 8A in
Monroe Township. This proposal was cancelled on December 1, 2006, after the
New Jersey Turnpike Authority decided to use funds to widen the mainline turnpike instead. By the 1990s, many traffic lights along the segment of US 1 in West Windsor and Plainsboro were removed and replaced with exit ramps and overpasses. As a result, the traffic lights at Scudders Mill, Plainsboro, Alexander, and Meadow roads were eliminated. This was followed by building ramps to replace the traffic light at US 130 and US 1 located North Brunswick, completed in 2003. An environmental impact study has been conducted by Rutgers University’s Transportation Policy Institute and Center for Negotiation and Conflict Resolution to improve US 1 through the Penns Neck area. This project would eliminate the Penns Neck Circle where US 1 meets Washington Road (CR 571) and move US 1 onto a new freeway alignment in the area. In addition, CR 571 is planned to be realigned to intersect US 1 further to the north. In 2009, the segment of US 1 between I-287 in Edison and the Garden State Parkway in Woodbridge was rebuilt to include new ramps at several intersections and removed access to a couple of roads in a $53.9-million (equivalent to $ in ) project that was intended to alleviate traffic and make this section safer. In 2013, the road was one of three that tied for the #1 ranking on the Tri-State Transportation Campaign's list of the top 10 most dangerous roads for pedestrians in New Jersey, New York, and Connecticut. The route, along with
US 40/
US 322 in
Atlantic County and
US 130 (Burlington Pike) in
Burlington County, were so ranked due to the nine pedestrian deaths that occurred on each of those roads from 2009 to 2011. ==Major intersections==