The section of highway through Newark is known as McCarter Highway. It parallels the Pennsylvania Railroad tracks up to Newark Penn Station. This portion was commissioned in 1934.
Between 1955 and 1959, the highway was extended northward as a freeway along the west bank of the Passaic River to an interchange with NJ 3. The road made it to the southern border between Clifton and Passaic by 1961. An extension to Paulison Avenue in Passaic opened in 1970, and a section to Monroe Street opened in 1974. For this last section, the river was rerouted, and the road clips Wallington in Bergen County without crossing today's river.
For a quarter-century, traffic headed for Paterson, New Jersey was dumped onto local streets in Passaic. Finally in 1998, construction began on the "missing link" of the freeway, which opened December 22, 2000.
Sections of McCarter Highway are being improved as of 2004, where the road passes features such as Bears and Eagles Riverfront Stadium, the New Jersey Performing Arts Center, and a new arena proposed for the New Jersey Devils. However, it is unlikely that this part of the road will ever become a freeway.
Between 1955 and 1959, the highway was extended northward as a freeway along the west bank of the Passaic River to an interchange with NJ 3.
Sections of McCarter Highway are being improved as of 2006, where the road passes features such as Bears and Eagles Riverfront Stadium, the NewJersey Performing Arts Center, and the Newark Arena under construction for the NewJersey Devils.
Route 21 was first defined in the 1927 renumbering, and was extended north to Paterson in 1948.
In NewJersey, the route of I-95 splits in two places, resulting in the existance of an "Eastern Route" and a "Western Route".
The Eastern Route cuts to the south and east of Trenton utilizing toll roads (the Pennsylvania Turnpike (I-276) and the NewJersey Turnpike (I-95)).
The NewJersey Turnpike mainline from Exit 7A to Exit 15, the NewJersey Turnpke Northern Extension, and the Bergen-Passaic Expressway connect continuously with both split routes.