 Interstate 78 | |
|---|---|
 I-78 highlighted in red | |
| Route information | |
| Maintained byPennDOT,DRJTBC,NJDOT,NJTA, andPANYNJ | |
| Length | 146.28 mi[1] (235.41 km) |
| Existed | 1957–present |
| NHS | Entire route |
| Restrictions | Nohazardous goods in theHolland Tunnel |
| Major junctions | |
| West end |  I-81 inUnion Township, PA |
| Major intersections |
|
| East end | Canal Street inNew York, NY |
| Location | |
| Country | United States |
| States | Pennsylvania,New Jersey,New York |
| Highway system | |
Interstate 78 (I-78) is an east–westInterstate Highway in theNortheastern United States that runs 144 miles (232 km) fromI-81 northeast ofHarrisburg, Pennsylvania, throughAllentown to western andNorth Jersey, terminating at theHolland Tunnel entrance toLower Manhattan inNew York City. Major metropolitan areas along I-78 include theLehigh Valley inPennsylvania, theGateway Region in New Jersey, and theNew York metropolitan area.
I-78 links ports in New York City andNorth Jersey to points west, including the Lehigh Valley, the third-largest metropolitan region ofPennsylvania. I-78 accommodates over four million trucks annually, representing 24 percent of all truck traffic in the nation.[2] It also is a major connection point to the New York metropolitan area's three major international airports,Newark Liberty International Airport,John F. Kennedy International Airport, andLaGuardia Airport.
| mi[1] | km | |
|---|---|---|
| PA | 77.95 | 125.45 |
| NJ | 67.83 | 109.16 |
| NY | 0.50 | 0.80 |
| Total | 146.28 | 235.41 |
I-78 begins at adirectional T interchange withI-81 inUnion Township, about 25 miles (40 km) northeast ofHarrisburg. Near the east end of the county, at exit 8,U.S. Route 22 (US 22) merges with I-78, and runs concurrently for the next 43 miles (69 km) throughBerks andLehigh counties.[3]
At exit 51, inUpper Macungie Township, US 22 leaves the highway. Drivers on I-78 eastbound must use this exit to accessI-476, also known as the Northeast Extension of thePennsylvania Turnpike, and westbound travelers must use exit 53 (northboundPennsylvania Route 309, PA 309) and then westbound US 22. From exits 53 to 60, I-78 runs concurrently with PA 309. The six-lane overlap bypasses the city ofAllentown to the south and crossesSouth Mountain.[4][5]
At exit 60 (A–B going westbound), PA 309 yields south toQuakertown.[6] Approximately six miles (9.7 km) east, there is an interchange betweenPA 412 and I-78 inHellertown, servingBethlehem andLehigh University. At exit 71,PA 33 reaches its southern terminus at atrumpet interchange. PA 33 traverses thePocono Mountains as it entersBangor and crossesI-80. The final exit on I-78 in Pennsylvania is Morgan Hill Road, which accessesPA 611 andEaston. I-78 then crosses theI-78 Toll Bridge and entersNew Jersey.
_between_Exit_36_and_Exit_33_in_Warren_Township%2c_Somerset_County%2c_New_Jersey.jpg)
After theI-78 Toll Bridge, I-78 enters New Jersey as thePhillipsburg–Newark Expressway.[7] The road begins by running parallel withCounty Route 642 (CR 642) in the town ofAlpha. At 3.94 miles (6.34 km), apartial cloverleaf interchange brings togetherUS 22,Route 122, andRoute 173 with I-78 inPhillipsburg.[8] US 22 now runs concurrently with I-78 for the next 15 miles (24 km). Going westbound, exit 4 leaves to the right forCR 637 andWarren Glen. The next exit, exit 6, is forCR 632 inBloomsbury. The route number is not signed on I-78. Exit 7 in Bloomsbury is the first of several eastbound exits for Route 173, which runs parallel the Interstate. Four miles (6.4 km) later, exit 11 leaves to the right as another exit for Route 173.CR 614 is located off the exit. Exit 12 westbound is for Route 173 again. Exit 12 eastbound is for afrontage road paralleling I-78.
Exit 13 is only westbound and is another exit for Route 173. Nearby the exit, going eastbound, the frontage road merges in.[8] Exit 15 is for Route 173 andCR 513 inFranklin Township. Exit 17 is forRoute 31 inClinton Township. InAnnandale, US 22 leaves I-78 at exit 18. US 22 continues toBound Brook andUnion County. At exit 20,CR 639 intersects. CR 639 heads to theRound Valley Reservoir. Exit 24 is forCR 523 toOldwick. At exit 29,I-287,US 202, andUS 206 interchange with I-78 inBedminster. At this point, inSomerset County, exits 33, 36, and 40 are for county routes inWarren Township. At exit 41, I-78 enters Union County[8] and then passes through theWatchung Reservation, where land bridges cross over the highway to allow for the safe passage of wildlife. At exit 45,CR 527 intersects after paralleling for some time. West of exit 48, I-78 splits into express and local highways. Exit 48 is forRoute 24 inSpringfield Township. Exit 49A is for one of Route 24's spur routes,Route 124. Exit 52 is for theGarden State Parkway inUnion Township. At exits 57 and 58,Route 21,US 1,US 9, and US 22 intersect I-78. The exit provides access toNewark Liberty International Airport.
East of exit 58 at the eastern tip ofNewark, I-78 becomes the Newark Bay Extension of theNew Jersey Turnpike. Past the first toll plaza, I-78 has an interchange withI-95 (New Jersey Turnpike) and crossesNewark Bay via theNewark Bay Bridge.[8] The first exit, 14A, is forRoute 440 inBayonne.Liberty State Park can be reached by taking exit 14B. Exit 14C is the final numbered exit, providing access to theLiberty Science Center.Route 139 runs concurrently with I-78 along aone-way pair of surface streets as it approaches theHolland Tunnel and entersNew York state.
I-78's length inNew York is 0.5 miles (0.80 km)—half of the Holland Tunnel and the egress-onlyroundabout immediately beyond the end of the tunnel. The route was planned to run east and north through New York City to end atI-95 inthe Bronx, but sections of the planned route, including theLower Manhattan Expressway, were canceled.
In New York City, I-78 continues through the egress-only roundabout known as the Saint John's Rotary. The five separate exits from the Rotary are assigned numbers, exits 1 to 5, in counterclockwise order. Exit 5, the last eastbound exit, leads ontoCanal Street. Under original plans, I-78 was to crossManhattan as the Lower Manhattan Expressway onto theWilliamsburg Bridge and then beyondI-278 onBushwick Expressway throughBrooklyn intoQueens near theJohn F. Kennedy International Airport. A section of I-78 at the airport was built as theNassau Expressway, laterI-878 and nowNew York State Route 878 (NY 878), though most of the westbound side was never built. Under the plans, east of the airport, I-78 would have turned north on theClearview Expressway, built north of Hillside Avenue in Queens and nowI-295, run across theThrogs Neck Bridge, and forked into two spurs, ending at I-95 via theThrogs Neck Expressway, which is nowI-695 and theBruckner Interchange via theCross Bronx Expressway, which is now part of I-295.[9]
I-81 west-northwest ofJonestown
US 22 east-northeast ofFredericksburg. The highways travel concurrently to east-northeast ofFogelsville.
US 222 west ofAllentown
PA 33 southwest ofEastonUS 22 east-northeast ofAlpha. The highways travel concurrently toAnnandale.
I-287 inBedminster
US 1 /US 9 /US 22 inNewark
I-95 in NewarkAll of I-78'sauxiliary routes serve New York City; however, none of these routes actually intersect I-78, following the route's truncation at the eastern end of theHolland Tunnel.
I-278 runs fromUS 1/9 inLinden, New Jersey, over theGoethals Bridge, throughStaten Island, over theVerrazzano–Narrows Bridge and throughBrooklyn andQueens, and across theTriborough Bridge intothe Bronx to end atI-95 at theBruckner Interchange.[11] I-278 was planned to extend west fromElizabeth, New Jersey, to I-78 inSpringfield Township, Union County, New Jersey,[12] and was to intersect I-78 at the east end of theWilliamsburg Bridge in Brooklyn.[13] Until 1972, I-278 ran along present-NY 895 and a proposed extension to I-95, while I-278 east of NY 895 was I-878.[14][15]
I-478 is an unsigned designation for theBrooklyn–Battery Tunnel, a spur from I-278 intoLower Manhattan.[11] Plans were made to continue it north along theWest Side Highway (NY 9A) to I-78 at the Holland Tunnel,[16]: 10 though the project was later canceled.[17]
I-678 runs from I-278 at the Bruckner Interchange south over theBronx–Whitestone Bridge toJohn F. Kennedy International Airport.[11] It was to intersect I-78 at its south end. Original plans took I-678 west on theGrand Central Parkway to I-278.[13][18]
I-878 is an unsigned designation for part ofNY 878, a short west–east freeway on the north edge of John F. Kennedy International Airport.[11] It was once planned as part of I-78 and now intersects I-678. The number was assigned in 1970.[19]In theLehigh Valley region of eastern Pennsylvania,PA 378, which exits in downtownBethlehem, was once I-378 but was predesignated as a state route after I-78 was rerouted to a new southerly alignment.I-178 was initially planned to extend inCenter City Allentown, but local opposition to the plan led to it being cancelled.
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Routes initalics are no longer a part of the system. Major Interstates are highlighted. | |
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