Conceived and built during the Great Depression, The Pennsylvania Turnpike is the Grandfather of the Interstate Highway System. The original roadway was a scant 160 miles long, running from Irwin, just east of Pittsburgh to Middlesex, just west of Harrisburg, Pa. This 160 mile piece of roadway, however, revolutionized automobile travel in the United States. The Pennsylvania Turnpike was the first roadway in the United States that had no cross streets, no railroad crossings, and no traffic lights over its entire length. A trip through the mountains of Pennsylvania with grades of no more than 3% was unheard of prior to this time. A four-lane superhighway through the Allegheny Mountains with unrestricted passing (except through tunnels), the Pennsylvania Turnpike even made the pages of Scientific American due to its state-of-the-art design and construction. One of the hallmarks of the original turnpike were the seven tunnels bored through the mountains of Pennsylvania. A trip on the turnpike with its seven tunnels was an exciting part of many family vacations in the days when only a handful of super-highways existed. Now that we have a nation-wide system of the toll-free Interstate Highways it is difficult to imagine how special a trip on the turnpike was back then.

The Pennsylvania Turnpike didn't actually start out as an idea for a superhighway. It really had its birth in the 1880's as a railroad conceived by William Vanderbilt of the New York Central Railroad and was intended to be competition for the Pennsylvania Railroad. Known as the South Pennsylvania Railroad, construction started late in 1883 and continued for two years. Nine tunnels were partially bored and 120 miles of roadbed were graded. Eventually, however, interest in the venture waned and in 1885, all work ground to a halt. For the next 50 years the abandoned right-of-way sat dormant until the the need for jobs during the great depression and growing popularity of the automobile helped push forth the idea of a super-highway using the old rail route.
View looking east through the eastern Kittatinny Tunnel portal to the Blue Mountain Tunnel portal. The valley between the two ridges is Gunter Valley, and there is only about 600 feet between the tunnels

During the roaring 20's, the automobile was beginning to come of age along with a prosperity that appeared would last forever. All of this came to an abrupt end, however, with the stock market crash of 1929 and the great depression of the 1930's. Unemployment was at a level never seen before, and Pennsylvania with her industry was hard hit. Several influential men who, as young boys, had played in the unfinished Vanderbilt tunnels began to toss around the idea of building a super-highway through the Allegheny Mountains of Pennsylvania to link Harrisburg and Pittsburgh. A perfect opportunity to give the local economy a shot in the arm both through jobs and a vastly superior transportation link between Pennsylvania's principal cities seemed an ideal project.

Through the involvement of Victor Lecoq and William Sutherland of the Pennsylvania Motor Truck Association, and state Representative Cliff Patterson, a study was commissioned to investigate the feasibility of a super-highway through the state. Using federal funds from the Works Progress Administration (WPA), teams of survey crews began scouring the mountains of central Pennsylvania in early 1936.
Arial view of the Blue Mountain interchange looking east at the time of the turnpike's opening.

The reports of the survey crews were favorable, and in 1937 the Pennsylvania Turnpike Commission was established with Walter A. Jones of Pittsburgh named the first commission chairman. The Turnpike Commission was given authorization to construct a 160-mile long 4-lane limited access superhighway through the Allegheny Mountains from Irwin (just east of Pittsburgh in Westmoreland County) to Carlisle (just west of Harrisburg in Cumberland County). This highway was the first of its kind in the United States.

Nobody had ever seen a road like this before, except at the General Motors Futurama exhibit at the 1939 New York Worlds Fair. Design features for the new road were:

Four 12-foot wide concrete traffic lanes - two in each direction
10 foot wide median strip and 10 foot wide berms
3 percent maximum grades (normal grades for roads through the mountains were 6-12 percent)
Maximum curvature of 6 degrees (most curves were 3-4 degrees)
Limited access design with 1,200 foot long entrance and exit lanes
Ten service plazas located along the right-of-way for traveler convenience
No cross streets, traffic signals, driveways or railroad grade crossings
11 Interchanges located (west to east) at Irwin, New Stanton, Donegal, Somerset, Bedford, Breezewood, Fort Littleton, Willow Hill, Blue Mountain, Carlisle, and Middlesex

The most impressive and conspicuous features of the Turnpike were the seven tunnels, with a combined length of nearly seven miles. The use of these tunnels would cut the cumulative climb between Pittsburgh and Harrisburg from nearly 14,000 feet traveling on U.S. Route 30 to under 4,000 feet. As one traveled from west to east tunnels were:

Laurel Hill Tunnel: Length: 4,541 ft.
Allegheny Mountain Tunnel: Length: 6,070 ft.
Ray's Hill Tunnel: Length: 3,532 ft.
Sideling Hill Tunnel: Length: 6,782 ft.
Tuscorora Mountain Tunnel: Length: 5,326 ft.
Kittatinny Mountain Tunnel: Length: 4,727 ft.
Blue Mountain Tunnel: Length: 4,339 ft.

The tunnels had large ventilation fans at each portal to keep carbon monoxide levels inside the tunnels at levels safe for motorists. (Ray's hill, the shortest of the turnpike's tunnels had ventilation fans at only one portal). Two of the original South Pennsylvania tunnels, the Quemahoning and Negro Mountain Tunnels were bypassed with open cuts near the tunnels.

Western Portal of Tuscarora Tunnel shortly before the opening of the Turnpike in 1940

Ground breaking ceremonies for the new road were held on October 27, 1938 on a farm in Cumberland County, and 9 months later the entire road was under contract. Concrete paving began in August of 1939, but inclement weather in early 1940 prevented paving so that by the spring of that year only 13 miles of roadway had been poured in concrete. As summer neared, however, the rate of completion increased to as much as 3 1/2 miles a day. Progress in the tunnels was obviously at a much slower rate and varied from about 11 to 36 feet per day, depending upon the amount and hardness of the rock that needed removed. None of the original Vanderbilt tunnels had been holed through back in 1885, and the tunnel which was most nearly holed through was at Kittatinny Mountain with about 550 feet remaining to be excavated. The remaining 550 feet of the Kittatinny Tunnel caused a lot of problems so it wasn't holed through first. The first tunnel to be "holed through" was the shortest: Ray's Hill on January 22, 1940. Consideration was given to building an eighth tunnel through Clear Ridge, just east of Everett, however, it was decided to dig a 150 foot-deep cut instead. This was the deepest highway cut in the United States at the time, and required the removal of approximately 1.1 million cubic yards of rock. The Clear Ridge Cut was dubbed "Little Panama" to capitalize on the famed Panama Canal, but the comparison was laughable since the amount of rock taken out of Clear Ridge could not come close to comparing to the more than 200 million tons excavated for the Panama Canal.

Besides the tunnels, the turnpike also had over 300 bridges and culverts. The longest of these was just east of the New Stanton Interchange and was a graceful curved bridge over 600 feet long. One of the requirements of the federal grants was that the turnpike was to be substantially completed by June 29, 1940. As spring turned into summer, it was rumored that Franklin Roosevelt would be on hand to open the highway on July 4, but that date came and went without the road being completed due to weather. Nearly three more months would pass before the road opened, and it was done so without ceremony. The Pennsylvania Turnpike opened at 12:01 A.M. on October 1, 1940 with only 12 hours notice.
Arial view of the New Stanton interchange and the New Stanton Viaduct. The gracefully curved viaduct was the longest bridge on the original turnpike at 660 feet.

Whether the Pennsylvania Turnpike could generate enough revenues from the collection of tolls was the subject of many a debate prior to its opening. The commission estimated that 1.3 million vehicles per year would use the new road while critics made estimates of as low as 260,000 vehicles per year. Using the turnpike cut the normal 5 1/2 hour trip between Harrisburg and Pittsburgh to about 2 1/2 hours, and from the very beginning the tremendous advantage in time savings generated traffic volume much greater than even the original planners and envisioned in spite of the tolls.

Traffic the first few days the Turnpike was open averaged about 6,000 vehicles per day. Sunday, October 6 was the first opportunity many people had to drive on the new road, and the Turnpike Commission was not prepared to handle the onslaught of people wanting to take advantage of that opportunity. Toll booths were thrown into pandemonium as thousands of Sunday afternoon sightseers tried to get off the Turnpike. Traffic was backed up for miles at some of the interchanges while toll booth attendants tried to collect tolls and return change. The traffic tie-ups were finally broken around 11:00 that night after an astounding 27,000 vehicles had used the new highway during the day. The following week the commission added temporary toll booths for fare collection at the interchanges, and those preparations paid off as about 30,000 vehicles used the road the following Sunday, but without the traffic backups of the previous weekend.

Initially, the Turnpike had no speed limit. Over the first several months, however, it became obvious that relying on mere common sense and nerve was not desirable and in April of 1941 a speed limit of 70 MPH was imposed (except for a 35 MPH speed limit in the tunnels). Even with the imposed speed limit, the advantages of the Turnpike over the other two main routes (State Route 22 and U.S. Route 30) were remarkable.
View looking through the eastern portal of the Blue Mountain Tunnel at the time of the Turnpike's opening

The Turnpike had only been open for a little over a year when the United States was drawn into World War II, and for the next four years the volume of traffic on the Turnpike was drastically curtailed, as was traffic elsewhere during the war. Because of the strategic value of the turnpike, special details of state troopers were stationed at the tunnels to stop any suspicious vehicles from entering the tunnels. Shortly after the war ended, however, traffic mushroomed and plans were made to extend the turnpike to Philadelphia and Ohio. The eastern extension to Philadelphia opened in November 1950 and the Western extension opened in stages in 1951. Traffic volume in 1950 reached 4.4 million vehicles - nearly 3 1/2 times what the planners had originally envisioned. In 1952 with both extensions open, traffic volume ballooned to 11 million vehicles. Taking into consideration the longer route (327 miles vs. the original 160 miles), this gave a traffic density of over 4 times the original estimates for the Turnpike.

Further plans were made to extend the turnpike across the Delaware River to connect with the New Jersey turnpike, and to extend the turnpike from a point near Norristown north to Scranton. These projects were completed in 1956 and 1957, respectively. The Northeastern Extension to Scranton required an eighth tunnel on the system through Blue Mountain. Since there was already a Blue Mountain tunnel on the system, the new tunnel was named the Lehigh tunnel because it is located along the northern border of Lehigh county. These were the last route expansion projects the commission undertook for 30 years because in 1956, President Eisenhower signed the Interstate Highway Act, putting an end to toll road construction in the U.S.
View of the Western Approach to Kittatinny Mountain Tunnel

By the 20th anniversary of the Turnpike, annual usage was 31 million vehicles over 470 route miles with a traffic density of about 8 times what the original planners had anticipated. Traffic tie-ups were occurring at the tunnel entrances and Laurel Hill Tunnel was a particularly troublesome spot. East-bound traffic had a seven mile climb approaching the tunnel and then had to squeeze down to one lane causing traffic back-ups stretching as much a five miles from the tunnel portal. Waits of 3 hours or more to get through Laurel Hill were not uncommon. Bottlenecks at the other six tunnels, while not as serious as Laurel Hill, were nonetheless troublesome. With competition from more modern east-west routes such as the New York Thruway and the future "Keystone Shortway" (Interstate 80), it was apparent that the Turnpike Commission needed to turn to making internal improvements.

The first of those improvements was to bypass the Laurel Hill Tunnel by routing the turnpike over Laurel Hill through a large cut to the north of the tunnel. The bypass featured a third lane for trucks and still maintained a maximum 3% grade as on the rest of the turnpike. The bypass required a massive 145-foot deep cut through Laurel Hill and the removal of 5.5 million cubic yards of rock - about 5 times that taken out of Clear Ridge. The bypass opened in 1964 and Laurel Hill Tunnel was closed.
The eastern portal of the Laurel Hill Tunnel as it appears today about 35 years after it was abandoned.

The second improvement was the addition of a second bore through Allegheny Mountain 125 feet to the south of the original tunnel. The interior walls of the new tunnel were lined with white ceramic tile for better visibility (the original tunnels had walls of exposed concrete) and more powerful ventilation fans. After the new tunnel was completed, the original Allegheny Tunnel was closed down for reconstruction. Both tunnels were open to traffic in 1966 providing 4-lane tunnel passage for the first time on the turnpike. Engineering studies also indicated that the most economical way to handle the tunnel bottlenecks at Tuscarora, Kittatinny and Blue Mountain Tunnels was to add parallel tunnels. Tunnels were added just south of the existing tunnels at Blue and Kittatinny Mountain and just north of the Tuscarora Mountina Tunnels.

Two more tunnels remained. Rays Hill and Sideling Hill tunnels were the shortest and longest tunnels on the turnpike respectively and lay about 5 miles apart just east of Breezewood. Rays Hill and Sideling Hill are joined by a ridge south of the existing turnpike and the two tunnels' close proximity to each other made it feasible to build a single 13-mile long bypass that would eliminate both tunnels. The bypass diverts from the original road just west of the original Breezewood interchange and climbs the western side of Rays Hill south of the old right-of-way. After cresting Rays Hill, the bypass runs parallel to the original road along the top of a ridge for a few miles before crossing over to the north side of the old turnpike a few hundred feet north of the eastern portal of the Sideling Hill Tunnel. The bypass joins the original road several miles to the east of Sideling Hill.
Eastern portal of the Ray's Hill Tunnel as it looks today. Notice that this portal has no equipment room to house ventilation fans. This was the shortest tunnel on the Turnpike, and as such presumably needed only one set of ventilation fans.

Please watch this site for possible future developments.

Do you have any questions, comments or suggestions?

Here are some links to other Pennsylvania Turnpike Web Sites:

Joseph Tropinka - Turnpike History, lots of postcard pictures & some maps

Michael G. Koerner - Topographical Maps of abandoned sections of the turnpike

Michael Natale - Some pictures of the original Ray's Hill - Sideling Hill section

South Penn Railroad - some history on the South Penn

Jeff Taylor - Several great pictures of the abandoned turnpike around Ray's Hill & Sideling hill

Charlie - Some links and a couple of pictures

John Duffy - Some interesting pictures of the old turnpike at the Ray's Hill - Sideling Hill bypass

NebulaSearch - A brief synopsis of the Turnpike with several links to various Turnpike sites

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