For more than six decades, the Pennsylvania Turnpike has served as a vital link to travelers throughout the Northeastern U.S. The essence of the turnpike is to surmount barriers of distance and geography to bring people together. Simply stated, the turnpike is all about connecting people. No image so plainly symbolizes this capacity to connect better than the tunnel. And while the turnpike operates 530 miles of highway across Pennsylvania today, the most vital components of this toll-road network are probably its five tunnels.
One of the great ironies in the history of transportation is the fact that “America’s First Superhighway” owes its existence to an ill-fated railroad. Construction on the South Penn RR started at the height of the railroad boom in 1883. But in 1885—with half of the grading finished and 5 miles of tunnels dug—work was halted when a treaty was struck with a rival line. The abandoned RR grading sat idle for 50 years and was forgotten in the undergrowth. Then, in the early 1930s, a state official got the idea to construct a toll bridge atop the old South Penn piers in the Susquehanna River at Harrisburg. The toll bridge idea evolved. Planners soon envisioned using the entire South Penn right-of-way and nine unfinished tunnels for a “forget-the-weather” highway linking Harrisburg to Pittsburgh.
The idea gathered political steam. An act authorizing the Turnpike Commission was signed into law in 1937. By mid-1939, all 160 miles of highway, seven tunnels (South Penn’s Quemahoning and Negro Mountain tunnels were bypassed) and 300 structures were under construction. The turnpike opened at one minute past midnight on Oct. 1, 1940.
“The most remarkable feature of the turnpike back in 1940 was the tunnels,” said Jim Stump, turnpike senior engineering project manager. “Nothing like it had ever been seen before, and it was quite a feat.” Because of the novelty of its seven tunnels, it was commonly referred to as the “Tunnel Highway” in the early days. And even though the toll road was built on a railroad bed and evolved from an idea for a toll bridge, it was the tunnels that inspired awe and wonder in motorists of that time.
From the original 160-mile toll road between Harrisburg and Pittsburgh, the turnpike grew, piece-by-piece. Sections were added to the east and west during the 1940s and 1950s, and the turnpike’s “Northeastern Extension”—110 miles from Philadelphia north to Scranton, Pa.—opened in its entirety in 1957. In the 1980s, the turnpike began constructing three western Pennsylvania expansion projects or offshoots: Turnpike 60, Turnpike 66 and Turnpike 43, also called the Mon-Fayette Expressway. Today, the commission operates more than 530 miles of toll roads.
Even though this expansion took place over four decades, the path to the present was not without its share of bumps and potholes. Along the way, the turnpike encountered growing pains as a result of skyrocketing traffic volumes. Traffic grew rapidly throughout the 40s and 50s; the seven, single-tube tunnels became choke points in the mid-1950s. Cars would back up for miles as two lanes were funneled into one. In most cases, the commission decided to build parallel "twin" tubes to relieve the logjam. But in some cases, it was more effective to bypass a tunnel. As a result, the number of original tunnels dwindled from seven to four.
The 4,541-ft-long Laurel Hill Tunnel—located about 60 miles east of Pittsburgh—was the first to be bypassed in 1964. Then, the 3,532-ft Rays Hill and 6,782-ft Sideling Hill Tunnels—located about 80 miles west of Harrisburg between Fort Littleton and Breezewood—were bypassed in 1968. The abandoned tunnels still stand today, and they have been used as sites for transportation field research. In fact, the Turnpike developed its Sonic Nap Alert Patterns there, the shoulder rumble strips used all over the nation. The idle Rays Hill and Sideling Hill tunnels and deserted highway have been converted into a biking trail.
A fifth tunnel was opened on the Northeastern Extension in 1950. The 4,461-ft Lehigh Tunnel on the Northeastern Extension (I-476) also started life as a lone tube; in fact, it was the last of the Turnpike's five tunnels to get a twin. The second Lehigh Tunnel opened to traffic on Nov. 22, 1991. This eliminated the final two-lane section on the entire Turnpike system.
