The parkway was constructed between 1946 and 1957 to connect suburban northern New Jersey with the Jersey Shore resort areas along the Atlantic coast and to alleviate traffic on traditional north–south routes running through each town center, such as U.S. Route 1 (US 1), US 9, and Route 35. During planning, the road was to be a toll-free highway designated as the Route 4 Parkway. Most of the highway north of the Raritan River is like any other expressway built in the 1950s through heavily populated areas. Between the Raritan River and the township of Toms River, the highway passes through lighter suburban development, while south of Toms River, the road mostly runs through unspoiled wilderness in the New Jersey Pine Barrens and swampland. The highway has seen many improvements over the years, including the addition and reconstruction of interchanges, bridge replacements, widening of the roadway, and removal of at-grade intersections. Previously, the road had been maintained by an agency known as the New Jersey Highway Authority (NJHA), however in 2003, the agency merged with the New Jersey Turnpike Authority (NJTA), which now maintains the parkway along with the New Jersey Turnpike.