Interchange of the Week-#53

Orientation: I-95, overlapped by US 1, runs left to right at top as it transits from the George Washington Bridge onto the Trans-Manhattan Expressway. This road disappears at right under the George Washington Bridge Bus Station. US 9 also runs over the bridge before turning northward on Broadway, the main street at right. Fort Washington Avenue is one block west of Broadway. The Henry Hudson Parkway (NY 9A) runs bottom to top at left, along the Hudson River shore. One block east runs Riverside Drive, which almost commingles with the parkway at top. The Trans-Manhattan Expressway is flanked by West 178th Street on the south and West 179th Street on the north; US 9 also follows these streets between Broadway and the bridge. West 181st Street is seen at top.

Exit numbers: Exit 1 on I-95 is for the Henry Hudson Parkway (NY 9A), and for Broadway (US 9) and West 178th Street. From the Henry Hudson Parkway, Exit 14 is for I-95 and the George Washington Bridge, while Exit 15 is for Riverside Drive (southbound, these two exits are served by a single ramp).

The interchange: This interchange combines a number of different elements, providing for a bewildering array of connections. The George Washington Bridge has two levels of traffic: the lower deck, almost totally obscured in the photo, just begins to appear in the open space west of the bus station. At this point, the lower bridge deck becomes the outer roadway of the Trans-Manhattan Expressway, while the upper deck becomes the inner roadway. (A similar situation arises in New Jersey, where the lower deck of the bridge feeds the outer [local] lanes of I-95.) Connections are available between the Henry Hudson Parkway, both bridge decks and the outer lanes of the Trans-Manhattan Expressway. This results in triple concentric loop ramps on the interchange's north side, as well as separate ramps from each level to and from Riverside Drive, which in turn seems to meld into the Henry Hudson Parkway here. In addition, the Port Authority's George Washington Bridge Bus Station and associated parking areas are situated above the Trans-Manhattan Expressway, and elevated ramps connect the bus terminal with the upper deck of the bridge. Added to this confusion are a number of local street connections, notably Broadway, where US 9 turns north off of the George Washington Bridge. The available movements from each approach are given below (thanks to David J. Greenberger for summarizing this information).

From George Washington Bridge (I-95/US 1/US 9 northbound) upper level: The left lanes of the bridge deck feed directly into the inner roadway of the Trans-Manhattan Expressway. The right two lanes form a single exit that branches and re-branches as follows: A connector roadway loops off first, running parallel to the ramp from the lower deck. It splits into separate ramps for the northbound and southbound Henry Hudson Parkway (NY 9A); from the former, there is yet another ramp for Riverside Drive (southbound). East of the connector, another ramp carries US 9 northbound onto West 178th Street at its intersection with Fort Washington Avenue. Finally, the last ramp carries buses into the George Washington Bridge Bus Station.

From George Washington Bridge (I-95/US 1/US 9 northbound) lower level: In this case, the bridge deck feeds directly into the outer roadway of the Trans-Manhattan Expressway. There is a single left exit for all connections. The first branch from this is a loop up to West 178th Street (US 9 northbound), with access to several side streets west of Fort Washington Avenue. From here the exit ramp runs parallel to that from the upper deck: the two approaches share an entrance to the southbound Henry Hudson Parkway (NY 9A), but there is a separate ramp to Riverside Drive. A left turn onto Riverside Drive provides access for the northbound Henry Hudson Parkway (NY 9A) and other points north.

From Trans-Manhattan Expressway (I-95/US 1 southbound) inner roadway: This approach feeds directly into the upper bridge deck. There are no exits available from the inner roadway, for it serves here, as in New Jersey, as the express roadway.

From Trans-Manhattan Expressway (I-95/US 1 southbound) outer roadway: This leads to the lower bridge deck. A ramp branches to the right just west of Fort Washington Avenue, forming the outermost of the triple loops. From this point, there is a connection to and from West 181st Street. After passing beneath the George Washington Bridge approach, this ramp joins that coming from the lower bridge deck, making the same connections to the Henry Hudson Parkway (NY 9A) and Riverside Drive. Note that in this case the connection to the southbound parkway requires an immediate weave to the far right.

From Henry Hudson Parkway (NY 9A) northbound: The exit 14 ramp branches off at bottom, crossing over Riverside Drive before splitting into three roadways. The left-hand roadway leads to the upper bridge deck (the middle loop of the three) while the right-hand roadway (the innermost loop) leads to the lower deck, which it joins from the left side. The center roadway merges into the outer lanes of the Trans-Manhattan Expressway. Just before this merge, there is a slip ramp (obscured here by the upper deck loop offramp) to West 178th Street (US 9 northbound). A second ramp from the parkway, Exit 15, makes a reverse curve to intersect Riverside Drive (southbound).

From Henry Hudson Parkway (NY 9A) southbound: This is a left-hand exit meeting Riverside Drive. Primary traffic flow here is southbound, although a left turn channel provides access to northbound Riverside Drive with its connection to West 181st Street. From southbound Riverside Drive, a loop ramp crosses over to meet the northbound parkway offramp, offering all the same connections. Again, there is a significant weave pattern for traffic bound for the lower bridge deck.

From Riverside Drive: At bottom, a right-hand ramp splits off to meet that coming from the Henry Hudson Parkway, connecting to both bridge decks, the outer lanes of I-95 northbound, and West 178th Street. Continuing on Riverside Drive, the road becomes one-way northbound at the southbound ramp from I-95. Just north of this is another split, barely discernible in the photo. The left fork, seen clearly, merges into the northbound parkway, while the right fork, obscured by trees, continues parallel to the parkway. Two-way traffic resumes at the turnaround loop just south of the bridge, and Riverside Drive continues on to serve West 181st Street and a small residential block. Beyond the top edge of the photo, this roadway merges once more into the northbound parkway.

From local streets: West 177th Street, one block south of the expressway, feeds directly into the offramp from the lower bridge deck and affords all the same connections. Similarly, West 181st Street has a connection (technically part of Haven Avenue) to the loop ramp from the outer lanes of I-95. West 179th Street, which carries southbound US 9 from Broadway onto the George Washington Bridge, feeds into the upper deck of the latter, and into West 181st Street by way of Cabrini Boulevard and other local streets. Finally, the George Washington Bridge Bus Station sits atop all of this with its bus-only ramps to and from the bridge; the crossover between these allows bus access to West 178th Street and from West 179th Street.

George Washington Bridge: Spanning the Hudson River between the Washington Heights section of Manhattan and Fort Lee, New Jersey, the bridge carries I-95, US 1 and US 9. US 46 also runs over the New Jersey portion, ending unannounced at the state line. The bridge feeds a toll-free section of I-95 maintained by the New Jersey Turnpike Authority. The bridge itself is a facility of the Port Authority of New York and New Jersey, as is the George Washington Bridge Bus Station.

No less intricate than the Manhattan-side interchange is the web of roadways, ramps and toll plazas in New Jersey (see closeup - 200 kb). Tolls are collected for Manhattan-bound traffic only, and there are separate plazas for the express (inner) lanes of I-95 and the local (outer) lanes. In addition, the Palisades Interstate Parkway has its own toll plaza for the bridge: the parkway connects to and from the bridge immediately west of the river. Besides this, various slip ramps connect the express and local lanes to each other, and to local streets such as (left to right) Center Avenue, Lemoine Avenue (NJ 67) and Hudson Terrace.

All text and images created by N. W. Perry unless otherwise credited.
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