County Route 501 is signed east-west in Middlesex County. The western terminus of County Route 501 is at CR 529 in South Plainfield. From there, the route heads east to Metuchen, where it has a short concurrency with Route 27. It then continues east, crossing the Garden State Parkway between Exits 127 and 129 in Woodbridge, following concurrencies with Route 184 and Route 440 to the southern section's eastern terminus at the Outerbridge Crossing.
In Bergen County, CR 501 leaves its concurrency with Route 63 in Palisades Park, using Central Boulevard to connect to the US 1/9/46 concurrency and Route 93. It is then concurrent with Route 93 until it reaches that route's northern terminus at Route 4 in Englewood. CR 501 continues north from this junction through Rockleigh, crossing the New York State Line and becoming New York State Route 340.
History
In 1808, the Perth Amboy Turnpike was legislated to run from Perth Amboy to Bound Brook. The company struggled to complete their road, having petitioned in 1820 to the state legislature to extend the time to complete the road. They were unsuccessful, as the road was only completed as far as Piscataway. Prior to being renamed in honor of John F. Kennedy in the 1960s, the John F. Kennedy Boulevard was known as Hudson Boulevard. While there was discussion of building a county long road as early as the 1870s, parts of Hudson County Boulevard were officially opened in 1896. By 1913 it was completed, and considered to be fine for "motoring", and included the road's eastern section, Boulevard East, into which Kennedy Boulevard forks at 91st Street. Taken as a single road, the circuitous route of west and east sections of the entire boulevard runs from the southern tip of the county at Bergen Point to its northern border with Bergen County and south again to the Hoboken city line. The Boulevard was named the fifth most dangerous road for pedestrians in New Jersey, and the most dangerous road in Hudson County for pedestrians in a February 2011 report by the non-profit Tri-State Transportation Campaign. The road was the location of six pedestrian fatalities between 2007 and 2009, which account for a little more than a fifth of Hudson County's 29 pedestrian deaths in the three-year period. In November 2017 county officials launched a safety campaign for Kennedy Boulevard's five most dangerous intersections, based on accident data:
County officials had expressed interest in building a pedestrian bridge that crosses Kennedy Boulevard at 32nd Street, at the Union City-North Bergen border since at least. The two cities contracted a company to build the bridge for just over $4 million in November 2010. Construction plans began in May 2011, and field work began later that August.