Interstate 78 originates in a rural area east of Harrisburg, Pennsylvania and ends at the Holland Tunnel linking Jersey City, New Jersey with Manhattan, New York. The freeway provides a trucking corridor to North Jersey from Central Pennsylvania in lieu of the tolled Pennsylvania and New Jersey Turnpikes. Through the Allentown, Bethlehem and Easton area, the freeway acts as a bypass along South Mountain and Morgan Hill to Alpha, New Jersey.
East from the Delaware River, Interstate 78 intertwines with New Jersey 173 (the former alignment of U.S. 22) across Musconetcong Mountain to the Spruce Run Reservoir area and Clinton. U.S. 22 emerges as its own route east from Lebanon to Newark while I-78 stays north to Berkeley Heights, New Providence and Summit. The two routes converge east from Union and Irvington at the interchange complex with New Jersey 21, U.S. 1 & 9 by Newark Liberty International Airport.
Beyond the U.S. 1 & 9 freeway leading north to Pulaski Skyway and Interstate 95, Interstate 78 travels the tolled New Jersey Turnpike Extension across Newark Bay to Jersey City. The limited access route ends at the one-way street couplet of 12th and 14th Streets between Jersey Avenue and the Holland Tunnel west portal. This stretch travels at-grade through four signalized intersections.
The Holland Tunnel carries motorists below the Hudson River to the area of Hudson Square and Soho in Manhattan, New York. Eastbound I-78 emerges at a loop encircling St. John’s Park with five ramps departing in succession to the adjacent street grid between Hudson and Varick Streets. The westbound beginning includes ramps from Canal Street, Watts Street and Varick Street two to three blocks to the north.
High Priority Corridor
Interstate 78 in New Jersey is part of High Priority Corridor 63: Liberty Corridor.
Parallel U.S. Routes
Interstate 78 parallels or directly replaced U.S. 22 from near Harrisburg, Pennsylvania east to Newark, New Jersey. The New Jersey Turnpike Extension loops to the south opposite U.S. 1 & 9 along the Pulaski Skyway.
Origins of I-78 predate the Interstate system with a 1950 upgrade of U.S. 22 to an expressway from the Lebanon County line to Exit 13 (PA 501). The four-lane roadway extended east from PA 501 at Bethel to Exit 17 (PA 419) in 1951. Work continued with construction of the Lehigh Valley Thruway from Allentown to the Delaware River commencing in 1952. The Thruway was finished in 1955, as was the portion between PA 419 and Exit 19 (PA 183 by Strausstown). When the Interstate system was established in 1958, two additional sections of U.S. 22 freeway were completed: Exits 23 to 30 (Hamburg) and from Exit 30 to the Lehigh County line.1
All of Interstate 78 west of the Lehigh Valley Thruway was completed in 1970.1 Resistance from residents of Phillipsburg, New Jersey in 1968 halted work on the connection from the Lehigh Valley Thruway to Interstate 78 east of Alpha. This led to the eventual realignment of I-78 to the south of Allentown, Bethlehem and Easton. Work on the new I-78 broke ground in 19841, with completion on November 21, 1989.2
Through New Jersey, Interstate 78 was completed in August 1986 when the controversial section through Watchung Reservation was finally opened to traffic.3 The New Jersey Turnpike Extension was constructed between 1954 and September 1956. The Holland Tunnel opened to traffic on November 13, 1927. It consists of a 8,371 foot long tube for eastbound and a 8,558 foot tube for westbound.4
The planned eastern extent of Interstate 78 through New York City included the following routes east and north to Interstate 95 in the Bronx:
- Lower Manhattan Expressway (unconstructed) – from the Holland Tunnel east to the Williamsburg Bridge
- Williamsburg Bridge (opened in 1903) – east to the Bushwick Expressway
- Bushwick Expressway (unconstructed) – east to the Nassau Expressway at Southern Parkway
- Nassau Expressway (completed eastbound in 1971, westbound unbuilt) – east to the Clearview Expressway
- Clearview Expressway (completed from NH 25 northward in 1963) – north to the Throgs Neck Bridge
- Throgs Neck Bridge – (opened in 1961) north to a split with Cross Bronx Expressway (I-78 mainline and Throgs Neck Expressway (I-78 Spur).
Interstate 78 was deleted through New York City between Interstate 278 (Brooklyn-Queens Expressway) and the planned junction of the unconstructed Bushwick Expressway at the Nassau Expressway by AASHTO on June 23, 1969. The same decision redesignated I-78 along the short Nassau Expressway as Interstate 878 and I-78 along the Clearview Expressway north from Hillside Avenue as Interstate 295.
East End – Manhattan, NY
West End – Lickdale, PA
Branch Routes – 4
Total Mileage – 146.28
Pennsylvania – 77.95
Cities – Allentown, Bethlehem, Easton
New Jersey – 67.83
Cities – Plainfield, Irvington, Newark, Jersey City
- Junctions –
New York – 0.50
Cities – New York City
Junctions – none
Source: December 31, 2018 Interstate Route Log and Finders List
I-78 Annual Average Daily Traffic (AADT)
|Location||Vehicles per day|
|Bethel Twp, PA||33,000|
|Holland Tunnel, NY||84,194|
Source: Pennsylvania Traffic Volume Map 2017 (Penndot)
2016 AADT NYSDOT Traffic Data Viewer
The majority of the proposed sections of Interstate 78 shown on this map in 1961 were never built. This includes the route southeast from the Williamsburg Bridge to Southern Parkway and the Clearview Expressway north to Hillside Avenue.
Portions of Conduit Boulevard were also expanded to accommodate the eastern most stretch of the Bushwick Expressway. A large grassy median remains in place from the canceled freeway.
U.S. 22 Interstate Proposal
In Section 1602 of TEA-21 (1998), Item 14 appropriated $100,000 to the study of including U.S. 22 between U.S. 250 and/or Interstate 77 in Ohio and Pittsburgh, Pennsylvania, within the Interstate Highway System. In July 1998, a group of highway officials from Ohio, Pennsylvania, and West Virginia met to discuss this issue. Their claim was that this upgrade would boost the area’s economy. Nothing further arose from this specific proposal since then, although sections of U.S. 22 constitute freeway standards through central Pennsylvania.
East End – East End of Holland Tunnel – Manhattan, New York City, New York
Combining with traffic from Route 139, Interstate 78 lowers to grade level at Jersey Avenue in Jersey City. Unsigned at this point, the ensuing three blocks of I-78 follow the couplet of 12th Street east and 14th Street west between the New Jersey Turnpike Extension and Holland Tunnel toll plaza. 08/09/04
Varick Street North at Holland Tunnel
Northbound Hudson Street connects with the Holland Tunnel west at Canal Street, one block beyond Vestry Street. Photo taken by Dan Moraseski (Winter 2001).
West End – near Lickdale, Pennsylvania
The first confirming marker for Interstate 78 east stands within the exchange at I-81. The freeway proceeds 5.8 miles east to PA 343 near Fredericksburg. Photo taken by Dan Moraseski (09/02/02).
West End Throwback
A new sign bridge replaced this assembly at the I-78 east and 81 northbound split by 2007. Photo taken by Jonathan Lebowitz (12/27/02).
Former button copy overheads at the ramp split for I-81 on I-78 west. 19 miles separate I-78 from the northern end of I-83 near Colonial Park. 01/94
Illuminated overheads previously posted at the unnumbered exit for I-78 east from I-81 south. This sign bridge was eventually replaced. 01/94
Replaced button copy overheads at the I-78/81 split. Prior to the Pennsylvania’s systemwide exit renumbering in 2001, many of the Interstate junctions were unnumbered. 01/94
- Pennsylvania Highways: Interstate 78.
- Celebrating the 50th Anniversary of the Eisenhower Interstate Highway System: Previous Interstate Facts of the Day by the Federal Highway Administration (FHWA).
- Interstate 78 (New Jersey), NYCRoads.com.
- Facts & Info – Holland Tunnel – The Port Authority of NY & NJ.
Page updated January 14, 2020.