This 2017 photo shows the westbound I-78 approaching EXIT 58 (Emaus Avenue) in Allentown. This section of I-78 was originally built as the PA 309 Bypass in the late 1950s, and was widened and upgraded to Interstate standards in the 1980s. (Photo by Steve Anderson.)

Length:


Constructed:

78.0 miles (125.5 kilometers)
43.0 miles (69.2 kilometers) co-signed with US 22
6.4 miles (10.4 kilometers) co-signed with PA 309
1950-1989

BEFORE IT WAS I-78: Plans for an improved highway along the US 22 corridor date back to early 1930s, when the Pennsylvania Department of Highways began construction of a direct route between the Lehigh Valley and Harrisburg. In 1932, the state designated this route as the "William Penn Highway." Although there was a continuous US 22 designation, the "William Penn Highway" actually was a collection of local roads.

Plans for an improved Harrisburg-to-Lehigh Valley highway were revived after World War II, when the state employed surveyors to help plan a relocation of US 22. These plans received a further boost in 1947, when a route between New York City and Harrisburg was included in the first Interstate highway map devised by the Federal Works Agency and the US Bureau of Public Roads. The original 33,700-mile (54,200-kilometer) highway network - which was selected in conjunction with the 48 states - did not have any funding mechanism in place, and for this reason, little progress was made nationwide.

Nevertheless, the Pennsylvania Department of Highways deemed it a priority to build a high-speed link for US 22 between the Harrisburg area and the Delaware River, anticipating the need for an Interstate highway link. In 1950, the state began work to relocate and improve US 22 from the current EXIT 8 (To US 22 West) in Fredericksburg, just west of the Lebanon-Berks county line, east to EXIT 17 (PA 419) in Bethel Township. This section was completed in 1951.

Next, the state shifted its focus to building the Lehigh Valley Thruway section of US 22 from the current EXIT 49 (PA 100) in Fogelsville east to the Easton-Phillipsburg Toll Bridge - a distance of 24.5 miles (39.4 kilometers) - including a span across the Lehigh River. This bypass had been planned since the early 1930s as a means of diverting traffic out of the downtowns of Allentown, Bethlehem, and Easton.
The section from PA 100 east to PA 145 was finished in 1953, followed by the completion of the section from PA 145 east to PA 987 at the Allentown-Bethlehem border (including a new span over the Lehigh River) in early 1954; this was followed by the completion of the section from PA 987 east to the Easton-Phillipsburg Toll Bridge in the fall of 1954. Concurrent with this project was the construction of a Berks County section from EXIT 17 east to EXIT 23 (Mountain Road) in Shartlesville.

In 1956, the state began work to complete the US 22 expressway through Berks and western Lehigh County. By 1958, an additional 21 miles (34 kilometers) of the new US 22 opened from EXIT 23 east to milepost 44, just east of the Berks-Lehigh county line. By 1959, the final gap in the US 22 expressway was closed with the opening of a five-mile (eight-kilometer) section from the Berks-Lehigh county line to the current EXIT 49.

The new freeway from Fredericksburg east to the Pennsylvania-New Jersey border originally received the preliminary designation of I-80N in late 1957, joining the I-80S designation (the original designation of the Pennsylvania Turnpike) near Harrisburg. In mid-1958, the freeway was re-designated Interstate 78, the main link between New York City and the Harrisburg area. An eventual connection to I-81 was still years in the future.

INADEQUATE AS SOON AS IT WAS BUILT: Although later sections of the new freeway had opened after the passage of the National Interstate and Defense Highways Act of 1956, they had been designed several years prior to its passage, meaning that these sections of US 22 - now I-78 - lacked adequate shoulders and acceleration-deceleration lanes. These sections also had poor sight distances, lower-than-accepted bridge clearances, higher-than-accepted grades, and a low median barrier (typically only a raised curb, or later a steel guiderail) separating opposing roadways.

BEFORE: This 2004 photo shows the westbound I-78 / US 22 at EXIT 30 (North 4th Street / Hamburg) prior to its reconstruction in the late 2000s. The original US 22 was rebuilt as a freeway through this area in 1956-1958 and added the I-78 designation in 1958, but still did not reflect updated Interstate highway design standards. (Photo by Alex Nitzman, www.aaroads.com.)

AND AFTER: This 2017 photo shows the westbound I-78 /US 22 at EXIT 30 after reconstruction. This section was updated with rebuilt overpasses, full-width shoulders, and extended acceleration-deceleration lanes. (Photo by Steve Anderson.)

A NEW ALIGNMENT SOUTH OF THE LEHIGH RIVER: As early as 1960, planners sought a bypass for existing US 22 along the Allentown-Bethlehem-Easton axis. The report prepared for the Easton Area Regional Planning Commission envisioned a new US 22 bypass extending from just west of Allentown, continuing south of the current US 22 alignment, and  crossing into New Jersey from Raubsville (about two miles, or three kilometers south of the current I-78 Toll Bridge). It was designed to relieve congestion along the Lehigh Valley Thruway, which carried both local and long-distance traffic.

The proposal gained momentum in 1963, when the Joint Planning Commission of Lehigh and Northampton Counties submitted a proposed bypass to the Pennsylvania Department of Highways. This was the first mention of an I-78 designation for the bypass, implying that the bypass would be eligible for 90% Federal funding. The day after the joint commission announced the plan, The Morning Call described the route as follows:

The suggested route would have Interstate 78 cut to the south of Phillipsburg in New Jersey, crossing the Delaware River, and entering Pennsylvania between Raubsville and Easton. It would continue in a westerly direction, skirting the south end of Glendon and Steel City, and moving along the Reading Railroad right-of-way at the Bethlehem Steel plant in Bethlehem. It would follow along the Lehigh River under the Hill-to-Hill Bridge, along River Road in Salisbury Township and into Allentown along Constitution Driver, then cut southwest toward the Susquehanna Street Bridge, and along the Reading Railroad tracks just southeast of the Queen City Airport industrial complex to meet with the Route 309 Bypass.

Route 309 would be utilized to a point just south of the Routes 22-309 interchange at Crackersport; here, a "transition" would be built, allowing a sweeping curve westward. The suggested route would cross the Northeast Extension of the Pennsylvania Turnpike and rejoin the present Interstate 78 west of Kuhnsville.

Unlike later proposals, this early I-78 alignment tracked closer to the south side of the Lehigh River shoreline, and was on the north side of South Mountain. Later proposals pushed I-78 to the south side of South Mountain.

The joint committee proposal was the first time that I-78 was proposed along an existing section of the PA 309 Bypass. Planning for the PA 309 Bypass began in the early 1950s, but work did not begin until early 1956. By the fall of 1958, the state opened a 7.8-mile (12.6-kilometer) section from PA 145 in Upper Saucon Township to just north of the Lehigh Valley Thruway (US 22) in South Whitehall Township. Under the joint commission proposal, I-78 was to use all but 1.8 miles (2.9 kilometers) of the PA 309 Bypass.

As the 1960s progressed, the joint committee proposal - which became known as the "Southern Corridor" - was among four I-78 alignments being studied by the state. The three other proposals were as follows:

  • The second proposal, which would have used the US 22 alignment in its entirety though the Allentown-Bethlehem-Easton area into Phillipsburg, New Jersey, had the disadvantages of 1) inadequate design on the Pennsylvania section, particularly in Easton; 2) the presence of Easton Cemetery, a historic property dating to 1849 that precluded widening and/or realignment; and 3) intense opposition in New Jersey, where community leaders feared a widened I-78 along the existing US 22 alignment would split Phillipsburg in two.

  • The third proposal had I-78 continue along US 22 east towards the 25th Street interchange in Easton, where I-78 would split from US 22 onto a new southeasterly alignment through developed sections of Easton towards the current I-78 alignment at EXIT 75 (PA 611). For this alternative, the presence of Hay's Cemetery, a historic cemetery dating to 1760 along this alignment, prevented the freeway's construction.

  • The fourth proposal had I-78 continue east towards the current PA 33 Expressway (which itself was not completed until 2002), then travel south towards the current I-78 alignment, where I-78 would continue east towards Pennsylvania. The Saucon Association for a Viable Environment (SAVE) favored the proposal as it would being built through Bethlehem's Saucon Park while avoiding developed areas in Bethlehem and Easton.

Officials felt the urge to act promptly because the states not only faced a 1972 deadline for getting I-78 built with Federal funds, but also had to determine the routing of key spur routes already approved: I-178 (Allentown Spur Route, never built) and I-378 (Bethlehem Spur Route, now PA 378). Meanwhile, the Delaware River Joint Toll Bridge Commission (DRJTBC) agreed to demands from Pennsylvania and New Jersey officials to build and open the new I-78 Delaware River bridge first and discuss tolling later. Even these demands did not accelerate construction of the missing link of I-78.

LINKING TO THE WEST AT I-81: While most of the attention focused on the Lehigh Valley, the state built its first new section of I-78 in 11 years in Lebanon County with the opening in 1970 of a 7.9-mile (12.7-kilometer) segment from EXIT 8 (US 22) in Fredericksburg west to EXIT 1 (I-81) in Union Township. The new segment, which included a partial slip-ramp interchange at EXIT 6 (PA 343) in Fredericksburg, was built to contemporary Interstate standards, including full-width shoulders, full-length acceleration-deceleration lanes, and a wide grassy median.

Toward the end of the 1970s, PennDOT proposed an another alternative route ("Deep Southern Corridor") that extended farther south and west, avoiding the PA 309 alignment altogether. However, by 1980, PennDOT decided upon the PA 309 alignment. (Image from Interstate 78: Final Supplemental Environmental Impact Statement, Federal Highway Administration and Pennsylvania Department of Transportation [1984].)

SOUTHERN CORRIDOR RECOMMENDED, BUT DELAYED: In 1972, the newly-created Pennsylvania Department of Transportation (PennDOT) submitted its recommendation for the Southern Corridor to the Federal Highway Administration (FHWA) after studying this alignment alongside alternate proposals for expanding US 22 (Lehigh Valley Thruway). PennDOT found that the Southern Corridor would result in less disruption than widening the existing US 22, which would have resulted in the loss of up to 950 residences, multiple businesses, and up to 650 acres of farmland.

However, PennDOT suffered a legal setback in 1974 when Judge John Fullam of the US District Court for the Eastern District of Pennsylvania ruled that I-78 must be rerouted away from Saucon Park unless no feasible alternative route could be identified. The court's ruling delayed the FHWA's approval of the Southern Corridor. In response, PennDOT developed a revised environmental impact statement for the Southern Corridor, including the section through Saucon Park. The updated  environmental impact statement for I-78, which PennDOT submitted in 1977,  had the following changes:

  • The I-78 alignment was moved slightly to the south, and the roadways placed on extended 0.4-mile (0.6-kilometer)-long viaduct, to minimize impacts to Saucon Park.

  • The proposed I-78 interchange with the Bethlehem Spur Route was east from Saucon Creek, where an elevated directional-T interchange (with a left-hand exit from eastbound I-78 to the northbound spur route) would have been built, to near the current EXIT 67 (PA 412), where a more modern T-interchange was planned. Upon completion, the Bethlehem Spur Route may have had the original I-378 designation reinstated.

  • As the left-hand eastbound exit ramp for the directional-T interchange was no longer required, the I-78 median was reduced to the allowable minimum of 36 feet (11 meters).

  • With the I-78/Bethlehem Spur interchange removed from the park, the total land taking was reduced to six acres, from 42 acres. Moreover, the removal of this interchange from park grounds no longer required the relocation of Saucon Creek.

  • No significant recreational facilities (e.g., softball fields, picnic grounds) would be affected.

Even as budget cuts prompted officials in 1977 to cancel numerous freeway projects across the commonwealth, particularly in eastern Pennsylvania, PennDOT saw the completion of I-78 as a priority and retained it on the state's highway plans.

This circa 1987 photo shows I-78 under construction near the present site of EXIT 71 (PA 33 Expressway) in eastern Lower Saucon Township. View is looking northeast towards Easton. The state overcame opposition from community groups, which had favored a different route away from Saucon Park. (Photo by Saucon Source, www.sauconsource.com.)

A MORE SOUTHERLY ALIGNMENT: In 1977, PennDOT also proposed a "Deep Southern Corridor" that differed from the longstanding Southern Corridor in that it did not use the PA 309 Bypass for both of its route. Instead, I-78 would have continued in a southwesterly direction from the current EXIT 60 in Lanark (Upper Saucon Township), passing the Pennsylvania Turnpike-Northeast Extension (I-476) in Emmaus (Upper Milford Township), then veering northwest towards the current I-78 near milepost 48 in Haafsville (Upper Macungie Township). Overall, the updated "Deep Southern" alignment had only three proposed interchanges at PA 309 in Lanark, PA 412 in Bethlehem, and Philadelphia Road in Easton.

The FHWA approved the "Deep Southern" alignment in 1979 with only a limited number of interchanges. However, PennDOT continued to undertake design work on the original Southern Corridor. Subsequently, PennDOT compared the impacts of both the Southern and Deep Southern corridors as follows:

  • SOUTHERN CORRIDOR: This corridor, estimated to cost $191 million in 1979 dollars, followed the PA 309 Bypass for 6.4 miles (10.4 kilometers) and required the acquisition of 55 residential properties and 32 businesses, primarily near what are now EXIT 56 (Cedar Crest Boulevard) and EXIT 57 (Lehigh Street). Agricultural takings were minimal because the alignment passed through a more urbanized area. The project involved widening the existing PA 309 Bypass from four to six lanes; as a result, the roadway featured an above-average grade of 5% and a median as narrow as nine feet, with a concrete Jersey barrier separating opposing traffic flows. The project also included an expansion of the spandrel arch bridge over Little Lehigh Creek in Allentown. Estimated average annual daily traffic (AADT) counts by 2010 were 70,000 along the PA 309 overlap and 50,000 outside the overlap.

  • DEEP SOUTHERN CORRIDOR: This corridor, estimated to cost $194 million in 1979 dollars, would have been 3.5 miles (5.6 kilometers) longer than the Southern Corridor, would have required the taking of 61 residential units, four businesses. Although the takings were greater for the Southern Corridor, the Deep Southern Corridor was found to have more negative impacts on agricultural land and natural habitats. It was also found to be more disruptive to residential communities. Estimated AADT counts by 2010 were 30,000 from US 22 east to PA 309, and 50,000 east of PA 309 to the Delaware River.

BACK TO THE SOUTHERN CORRIDOR: Despite the FHWA's prior approval of the "Deep Southern" corridor, PennDOT announced in 1980 that it preferred the original Southern Corridor, as it had the support of the cities of Allentown, Bethlehem, and Easton, the Northampton County Council, the Lehigh Valley Transportation Study Coordinating Committee (the metropolitan planning organization for Lehigh and Northampton Counties), and the Pennsylvania Department of Agriculture. Only the Lehigh County Board of Commissioners favored the "Deep Southern" alternative, citing concerns about heavy traffic on the existing PA 309, though PennDOT responded to the commissioners that using the PA 309 corridor would provide an optimal balance of meeting the area's transportation needs while preserving the environment. Local business leaders also echoed this view.

In early 1984, PennDOT submitted its final environmental impact statement of the I-78 Southern Corridor using the PA 309 corridor. The FHWA subsequently approved PennDOT's submission, which called for six through lanes of traffic on the I-78 / PA 309 overlap, and four through lanes on the remaining sections.

This 2017 photo shows the westbound I-78 at EXIT 53 (PA 309 Bypass) in Allentown. Northbound PA 309 departs from I-78 at this exit, and continues north towards Hazleton and Wilkes-Barre. Note the erroneous PA 476 shield where an I-476 shield should be used instead to direct motorists to the Pennsylvania Turnpike-Northeast Extension. (Photo by Steve Anderson.)

"There will be a honeymoon period, but a highway is just a highway." - James Bergmaier, PennDOT District 5 Community Relations Coordinator upon the completion of Pennsylvania's I-78 in 1989, as reported in The Morning Call.

AT LONG LAST, INCHING TOWARDS COMPLETION: Construction began in the summer of 1984 on the missing link of I-78 from PA 309 in Saucon Valley towards the Delaware River bridge. Around this time, work also began on the seven-span Interstate 78 Toll Bridge connecting Williams Township in Pennsylvania with Alpha Township in New Jersey. The bridge required Congressional approval for its construction: although the bridge was paid with 90% Federal funding and 10% state funding, special legislation had to be passed in order for the DRJTBC to collect tolls.

Construction was delayed until 1986 for the short I-78 segment linking US 22 with PA 309 west of Allentown, mostly for utility relocation. Work on this segment included improvements to the existing I-78 from the I-78 / US 22 split west to EXIT 49 (PA 100).

By 1988, the reconstruction and widening of the dual-signed I-78 / PA 309 section, including the Little Lehigh Creek bridge, was completed and open to traffic, while the Saucon Park viaduct, while completed, had yet to be connected to other sections of I-78. Nevertheless, work was well underway on the remaining sections, though the presence of large sinkholes west of PA 309 in Upper Macungie Township west, and west of PA 412 in Hellertown, proved a challenge for construction crews to meet the fall 1989 deadline.

Finally, on November 21, 1989, the 26.2-mile (42.3-kilometer) missing link on I-78 - one of the last remaining missing links on the mainline Interstate highway system - was opened to traffic, along with the Interstate 78 Toll Bridge to New Jersey. A last-minute lawsuit by a Lehigh County developer, who sought to delay the opening of I-78 so that sound walls could be built, did not prevent the opening of the $450 million missing link.

This 2010 photo shows the westbound I-78 at EXIT 71 (PA 33 Expressway) in Easton. The PA 33 Expressway --another freeway extension delayed by decades -- was extended south to I-78 in 2002. (Photo by Steve Anderson.)

A LONG-AWAITED CONNECTION: Construction of the long-delayed PA 33 extension from US 22 south to I-78 began in March 1999. Like the rest of the expressway, this section of PA 33 has two through travel lanes in each direction, though a wide grassy median could accommodate a third travel lane in each direction. The highlight of this section is a six-span, 1,870-foot-long steel bridge that rises 180 feet over the Lehigh River. The bridge has a main span of 594 feet, and about 13.5 million tons of steel were used in its construction. The $104 million extension, which included construction of a park-and-ride lot at Freemansburg Avenue (unsigned EXIT 2), was completed in January 2002.

REHABILITATION AND MODERNIZATION: According to PennDOT, traffic counts (AADT) on Pennsylvania's I-78 are as follows:

  • 35,000 through Berks County;
  • 45,000 through western Lehigh County (west of PA 100);
  • 75,000 through central Lehigh County (from PA 100 east to PA 309 eastern split);
  • 60,000 through eastern Lehigh and western Northampton Counties (from PA 309 eastern split to PA 33 Expressway); and
  • 75,000 from PA 33 Expressway east to the Interstate 78 Toll Bridge.

In recent years, PennDOT has been addressing the need to bring I-78, particularly west of the Lehigh Valley, to modern Interstate standards. During the 2000s, projects on I-78 west of the Lehigh Valley focused on improving pavement and adding shoulders, replacing the median with a tall concrete "Jersey" barrier, and rebuilding underpasses with higher vertical clearances and shoulders. More recent and current key projects are as follows:

  • In 2019, PennDOT completed a four-year project to replace an antiquated partial-cloverleaf interchange design with tight ramps to a diamond interchange at EXIT 40 (PA 737) in Kutztown. The $47 million project also improved the roadway geometry of PA 737, such that PA 737 passes I-78 at a more subtle angle.

  • From the mid-2010s through 2025, PennDOT rebuilt the area around EXIT 29 (PA 61) in Hamburg (Berks County). The $135 million project included rebuilding the PA 61 bridge over I-78, replacing the full cloverleaf interchange with a reconfigured partial-cloverleaf with wider ramps, widening and rehabilitating the I-78 mainline arch bridge over the Schuylkill River, and widening the I-78 bridge over Port Clinton Avenue on the east bank of the Schuylkill River.

  • PennDOT began work in 2024 on a $123 million replacement of the I-78 bridge over Maiden Creek and PA 143 (near EXIT 35) in Greenwich Township (Lenhartsville). The project, which will add auxiliary lanes for EXIT 35 and full shoulders, is slated for completion in 2028.

  • In 2026, PennDOT will begin improvements on I-78 from EXIT 67 (PA 412) east to EXIT 75 (PA 611). The work will include repaving, upgrading drainage, adding a truck climbing lane westbound, and improving the interchange at EXIT 67.

  • PennDOT also plans a long-term improvement from EXIT 45 (PA 863) in New Smithville east to EXIT 49 (PA 100) in Fogelsville. The project will include widening (either through the addition of truck climbing lanes or a full widening to six lanes [three in each direction]), the reconfiguration of the cloverleaf interchange at EXIT 49 (either as a diamond or single-point urban interchange ["SPUI"], and the construction of a new interchange at EXIT 48 (Adams Road) to serve nearby warehouses and distribution centers. The timetable and scope of this work is still being considered, though any work is unlikely until at least 2030.

WHAT WON'T GET DONE: PennDOT has no current plans to build an interchange for EXIT 63 (PA 378) in Lower Saucon Township. The state considered an interchange at this location when plans for the I-78 Southern Corridor were developed, and some business groups petitioned the state to build an interchange to help develop the area. However, PennDOT sided with local groups seeking to prevent development in that area, seeking instead to have the primary access from I-78 to Bethlehem via the Bethlehem Spur Route. When the Bethlehem Spur Route was canceled, PennDOT shifted its focus to improvements along PA 412 between I-78 and Bethlehem's South Side.

This 2013 photo shows the westbound I-78 at milepost 42.9 in Berks County. Since 2000, PennDOT has made significant improvements to I-78, particularly the section of the Lehigh Valley whose construction predated the Interstate highway era. (Photo by David Golub, www.eastcoastroads.com.)

I-78 should be widened to six lanes west from the I-78 / US 22 split west of Allentown to EXIT 45 (PA 863) in New Smithville, and from EXIT 60 (PA 309 Bypass) in Lanark east to the Interstate 78 Toll Bridge.

SOURCES: "Super Speed Highway Project and New Lehigh Valley Bridge Gets Support of Entire Valley," The Morning Call (5/03/1931); "William Penn Highway Route Is Sustained," The Morning Call (2/26/1932); "Survey of Route 22 Change To Start Soon," The Morning Call (8/03/1946); "State To Resurface and Widen Route 22, Bethlehem to Easton," The Morning Call (3/20/1947); "State Highway Department  Officials Cite Need for Funds To Improve Roads," The Morning Call (5/12/1948); "Engineer, Councilmen To Air 309 Plans," The Morning Call (5/23/1953); "Four-Lane Highway Opened Linking Route 309 at Walberts to Bypass at Crackersport," The Morning Call (11/17/1953); "Sumner Avenue Bridge To Be Repaved Before Route 22 Bypass Opening," The Morning Call (11/17/1953); "Plans Almost Ready for Route 309 Bypass," The Morning Call (3/01/1956); "No Objection to Proposed 309 Bypass," The Morning Call (11/03/1956); "Traffic Pattern at 309 Bypass South End Confuses Motorists," The Morning Call (11/01/1958);  "Easton Development Keyed to Planning, Civic Action, "The Morning Call (1/20/1960); "3-City Bypass May Parallel River, Rails" by Phil H. Storch, The Morning Call (11/15/1963); "State Expected To Act Soon on Shifting Route 78" by Phil H. Storch, The Morning Call (12/19/1963); "Interstate 78 to South Preferred by Bethlehem," The Morning Call (2/13/1964); "2-County Planners Give Priority to Spur Routes," The Morning Call (10/22/1964); "Bridge Toll Issue Shelved To Rush Interstate 78," The Philadelphia Inquirer (12/19/1965); "Agency Clears Study on Thruway Upgrading," The Morning Call (11/12/1966); "Turnout Too Large, I-78 Hearing Postponed" by Phil H. Storch, The Morning Call (04/18/1968); "Thruway Upgrading Urged as I-78 Alternate Plan" by Vince Zaffiro, The Morning Call (6/20/1970);  South Side '76 Plan Bethlehem, Gruen Associates (1972);  "State To Start I-78 Takings," The Morning Call (6/15/1973);  Interstate Route 78: Draft Continuing Environmental Evaluation Document, New Jersey Department of Transportation and Pennsylvania Department of Transportation (1973); "I-78 Ruling Disappoints Chamber, Foes Glad" by Ted Mellin, The Morning Call (5/04/1974); "I-78 Report in Washington" by David Kluski, The Morning Call (6/08/1977); Saucon Park: Revised 4(f) Statement, City of Bethlehem, Northampton County , Pennsylvania (1977); "Highway Planners Predict Favorable Outcome for I-78" by Gary Sanborn, The Morning Call (11/15/1978); "DOT Approves I-78 Plan" by Gary Sanborn, The Morning Call (8/23/1979); "PennDOT: I-78 Will Use Route 309" by Paul Lowe, The Morning Call (6/20/1980); "Route 309 Chosen for I-78" by Dan Pearson, The Morning Call (6/09/1983); "PennDOT Is Gathering Information for Lehigh County Portion of I-78" by Dan Pearson, The Morning Call (6/07/1984);  Interstate 78: Final Supplemental Environmental Impact Statement, Federal Highway Administration and Pennsylvania Department of Transportation (1984); "Interstate's Bridge, Viaduct To Be Completed This Year" by Dan Pearson, The Morning Call (2/22/1987); "I-78 Job More Than Half Finished, but Behind Schedule" by Dan Pearson, The Morning Call (8/16/1987); "A Bridge, A Vision Designers Want the I-78 Span To Move You: Physically and Aesthetically" by Rosa Salter, The Morning Call (8/25/1987); "1988 Is 'Year of the Big Push for I-78" by Dan Pearson, The Morning Call (4/20/1988); "Allentown-Area Road Link To Open," The Philadelphia Inquirer (11/11/1989); "Just a Snip of the Ribbon, and the Rest Will Be History" by Tom Lowry, The Morning Call (11/21/1989);  Route 33 Extension, Route 22 Interchange to Route 78 Interchange, Final Environmental Impact Statement, US Department of Transportation and Pennsylvania Department of Transportation (1993); "Long Journey for Route 33" by Dianne Knauss, The Morning Call (3/04/2001); "Three Decades of I-78: See Rare Photos of 78 Under Construction" by Josh Popichak, Saucon Source.com (3/30/2019); "Route 22 Widening Cut as PennDOT Shifts Funding to Interstate 78, with $395 Million in Improvements" by Tom Shortell, The Morning Call (12/04/2019);  "I-78 or Anti-78? Fight Over Interstate 50 Years Ago Still Sounds Familiar Today" by Steve Novak, The Express-Times (11/27/2022); "The Road Scholar: What's It Going To Take To Whip Interstate 78 into Shape?" by Tom Shortell, Lehigh Valley Public Media (3/16/2025); Delaware River Joint Toll Bridge Commission; HistoricAerials.com; Jeff Kitsko.

  • I-78 shield by Ralph Herman.
  • US 22 and PA 309 shields by Steve Anderson.
  • Lightposts by Millerbernd Manufacturing Company.
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INTERSTATE 78-PENNSYLVANIA LINKS:

INTERSTATE 78-PENNSYLVANIA CURRENT TRAFFIC CONDITIONS:

INTERSTATE 78-PENNSYLVANIA VIDEO LINKS:

THE EXITS OF METRO PHILADELPHIA:

  • I-78 (Pennsylvania) exit list by Steve Anderson.

  • Interstate 78 Toll Bridge

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