Today's stretch of NJ 4 was completed by 1934, not long after the opening of the George Washington Bridge in 1931. With the opening of both the Bridge and Route 4, much of Bergen County became accessible to those who wished to escape to the suburbs, but wanted to retain easy access to New York City. From 1920 to 1940, despite the slowdowns resulting from the Great Depression, Bergen County's population nearly doubled, growing from 210,643 to 409,646 residents in that twenty-year period.
Originally, NJ 4 was projected to go all the way to Cape May. Parts of Route 35 and U.S. Route 9 south of Woodbridge Township bore the NJ 4 designation prior to 1953. The Garden State Parkway was originally designed to bypass this stretch of NJ 4, and a stretch built prior to 1953 between Union and Woodbridge Township appeared on maps as "4 PKY". To this day, the New Jersey Department of Transportation's internal reference number for the Parkway is NJ 444, commemorating the proposal.
Broadway continues east with businesses lining both sides of the roadway, and runs concurrently with Route 4 through Fair Lawn, ending at the interchange of Route 208. Route 4 continues on the same path east. While not a freeway yet, the access to the road becomes limited, but businesses still line the road. Route 4 then enters Paramus and its huge shopping district. There it has an interchange with Route 17. As the road leaves Paramus it becomes a freeway and businesses no longer line the route. Route 4 then enters River Edge, Hackensack, Teaneck and Englewood. In Teaneck, Eastbound Route 4 goes from three lanes down to two at the Belle Avenue exit, widening back to three lanes when the highway approaches Englewood. This constriction causes frequent backups during morning rush hours and many other points throughout the day. Route 4 then ends at U.S. Route 9W, a huge interchange at the George Washington Bridge approach.
Route 4 had several former spur routes: