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Interchange Index

Overhead Picture from terraserver-usa.com

Overview: I present to you one of the biggest, most sprawling, most screwed-up, but yet most functional interchanges I have ever seen. The major east-west highway at center is NJ 440, which runs from the New Jersey Turnpike in the west to Staten Island in the east. The two major north-south highways intersect NJ 440 to the right of the center of the photo. The Garden State Parkway (the wider of the two highways) enters just west of US 9, and the parkway leaves the north end of the photo inside US 9. Notice that both of these highways leave the south end of the interchange on bridges; they are about to cross the Raritan River, which runs just south of this photo. The interchange is also intersected by many local roads. Smith Street (Middlesex CR 656) runs parallel to and south of NJ 440, from left center to bottom right. The road leaving the north side of the aerial photo is Crows Mill Road, which is also CR 656. (The southern half of Crows Mill Road, although not directly involved with the interchange, is visible where it intersects Smith Street about halfway from the western edge of the photo to the Garden State Parkway.)

Interchange Description:The easiest way to narrate the complex structure of this interchange is to run through the entrances and exits of each highway. (Note: SB=southbound, NB-northbound, EB=eastbound, WB=westbound.)

• NJ 440 Eastbound: Coming into the interchange, the first exit ramp serves Smith Street and Crows Mill Road through a pair of modified cloverleaf interchanges. After two underpasses, another ramp leaves NJ 440 for US 9 SB. After a railroad overpass, a slip ramp leaves NJ 440, joins a ramp from Smith Street, and enters the Garden State Parkway SB. The next feature is a long viaduct over the Garden State Parkway, US 9, and about half a dozen other ramps. The next ramp splits after leaving NJ 440. The right fork is a loop ramp which provides access to US 9 NB. Traffic bound for the Garden State Parkway NB uses this ramp, and switches from US 9 to the parkway at exit 128, a mile north of here. The left fork of this exit leads down a ramp which eventually intersects Florida Grove Road (Middlesex CR 655), and provides indirect access to Smith Street. Finally, two ramps join NJ 440. The first is from Smith Street and, indirectly, Garden State Parkway SB and US 9 SB. The second is from the parkway and US 9 NB.
  
• NJ 440 Westbound: The first offramp westbound runs north, alongside the railroad line, over US 9 and the parkway, and joins Smith Street WB. After crossing the parkway, another ramp leaves NJ 440 and splits, providing access to US 9 and the parkway SB. Three ramps join NJ 440 as it leaves: one from both directions of US 9 and the Garden State Parkway, one from Smith Street, and one from Crows Mill Road.
  
• Garden State Parkway Northbound: All traffic leaving the parkway does so via one ramp (Exit 127), which leaves just south of the NJ 440 overpass. This ramp first has a left fork shich goes to US 9 NB. The remainder of the traffic is split between NJ 440 WB/Smith Street WB and NJ 440 EB/Florida Grove Road. Any traffic entering the Garden State Parkway NB does so by way of US 9 NB, and enters the parkway at the split between US 9 and the parkway at exit 128.
  
• US 9 Northbound: US 9 splits just north of Smith Street. The right fork has two ramps; the first is to NJ 440 EB and Florida Grove Road, and the second leads to NJ 440 WB and Smith Street WB An onramp from the Garden State Parkway NB joins the left side of the right fork just before the railroad overpass. The left fork has no exits, but one onramp (on the right side) from Smith Street and NJ 440 EB. The two halves of US 9 NB join again just north of the railroad overpass. I'm not sure how this is signed, but my guess is that through traffic is directed to use the left fork, while traffic bound for New Brunswick Avenue (the next exit to the north) uses the right fork. By splitting the NB lanes, weaving is avoided inside this interchange and between here and the New Brunswick Avenue exit.
  
• Garden State Parkway Southbound: Southbound traffic exiting the Parkway does so north of this photo, and joins US 9. (see below) Traffic enters the southbound lanes at two points. The first is from NJ 440 WB, just north of the NJ 440 bridge; the second is from Smith Street and NJ 440 EB.
  
• US 9 Southbound: The first exit from US 9 southbound leads to NJ 440 WB and Smith Street WB. A second ramp, just south of NJ 440, leads to Smith Street EB (and, via a U-turn ramp in the median of Smith Street, to Smith Street WB and Crows Mill Road.). Just after this ramp leaves, atraffic joins the left side of US 9 SB from NJ 440 WB and Smith Street EB. Lastly, just before the beginning of the Raritan River Bridge, another ramp joins from Smith Street WB.
  

Missing Connections: Despite the large number of ramps here, a number of connections are not available directly. Naturally, traffic cannot make the "U-turn movements," for example, from the Parkway NB to US 9 SB, or vice versa. However, one important pair of connections is missing: Traffic cannot directly access the Parkway NB/US 9 NB from NJ 440 WB, or NJ 440 EB from the Parkway SB/US 9 SB. Both of these connections are provided by New Brunswick Avenue, which intersects NJ 440 and US 9 just north of this photo, or via other streets through Woodbridge. Also, Crows Mill Road is not directly connected to NJ 440 EB or the Parkway/US 9; these connections are also available via New Brunswick Avenue.

History: Before the construction of the NJ 440 expressway, the interchange here had a totally different look. Very few of the ramps here existed, Smith Street did not exist west of US 9, and Crows Mill Road was continuous through what is now a mess of ramps. The Garden State Parkway actually ran outside of the US 9 lanes north of here; these two highways switched positions when NJ 440 was added. Exit 127 was for US 9, and Exit 127A (since removed) werved New Brunswick Avenue. (Thanks to the SPUI Freeway Website for a little help on this point - see the link at the bottom.)

Advantages: Despite the intimidating mess of ramps and roads, this interchange actually functions reasonably well. To begin with, there is very little weaving; there is none on NJ 440, the Parkway, or US 9. The design even avoids weaving between onramps to US 9 NB here and NB offramps at New Brunswick Avenue. Much of this is accomplished through the split in the NB traffic on US 9. What little weaving is present is relegated to lesser ramps and Smith Street. The designers here also avoided left exits and entrances on NJ 440 and the Garden State Parkway.

Disadvantages: The only real disadvantage here is sheer cost. The number of bridges present here is phenomonal, and much less pavement and concrete could have been used. (of course, at the cost of a less safe and leses functional interchange) The junction, especially the western half at Crows Mill Road and Smith Street, is sprawling, and uses a large amount of real estate in an important industrial area. However, these drawbacks are more than made up for in the functionality of the interchange.

Corrections? Suggestions? More information is always welcome.
Suggestions for more interchanges to cover on this site are great too.
Contact the author, Dan (known as DanTheMan on misc.transport.road):
twowheel@email.com