With the opening recently of the Pennsylva: Turnpike, American motorists took possession of a 160-mile stretch of superhighway, road such as has been seen hitherto only in miniature at the Futurama at the World's Fair. This super-speed, super-safe route, the longest of homogeneous design in the country, has no sharp curves, no steep grades, no cross trafic from one end of its valley-leaping, mountain-piercing course to the other, writes Reginald W. Cleveland in the New York "Times." Such a road would be an engineering achievement in any locality. But the turnpike is the more remarkable in that its way lies through the most difficult terrain in the Eastern United States. In a series of seven great tunnels and numerous colossal cuts it bores through the Appalachian Mountain barrier, which stretches its unbroken chain of rocky summits and ridges from Central New York to Central Georgia.
Hitherto a car or truck heading west from any point on the Middle Atlantic Coast was obliged to traverse the cutbacks, tortuous meanders, laborious climbs and perilous descents of typical mountain roads before it could reach the plains of the Middle West. The broad concrete ribbon* of the Pennsylvania Turnpike, provides a direct highway link between these two great regions of big cities. From the western environs of Harrisburg, whither roads converge from New York, Philadelphia and Baltimore, it runs westward to the outskirts of Pittsburgh. The part that such a road is prepared to play in national defence needs no pointing out.
There are seven tunnels in 100 miles, and there are amazingly deep cuts where, from the approaching car, it looks as if some super-Paul Bunyan had gouged a great, blunt-ended, pie-shaped segment out of the surface of the brown earth. All told, the cuts and fills and tunnels reduce the aggregate climb along the Turnpike from 13,000 feet toa little more than 3,000. They result in a maximum grade of 3 per cent., which is less than an eight-foot rise in the length of a standard city block.
Inside the tunnels the roadway narrows to a single lane in each direction with no separate ing strip. But the tunnels average less than one mile in length. It is only by driving this great toll road that one can realize what a boon to the motorist has been created by Federal grant and by bond issue along the right of way of that forgotten dream of the Fifties, the South Penn Railroad that never was built.
Most Extensive Elaboration For this road, by far the most extensive American elaboration upon the German system of Autobahnen, is essentially a driver's road. There is no access for pedestrians; no frontage for any commercial use. For its entire length it is, in fullest conception, a vehicular freeway-Its advantages in speed, fuel economy and safety over the existing roads between Pennsylvania's capital city and Pittsburgh are expected to lead to a use, under the toll system, which will enable the retirement of the $40,800,- 000 of bonds purchased by the RFC long be-lore their due date 30 years hence and make the road free in the literal sense. Tolls are $1.50 for passenger cars, one way, and $2.25 round trip.
Safety of operation has been the keynote of the Turnpike design. Because there is not a crossing at grade there is no need for a traffic light. There are two 12-foot lanes in each direction, the two pairs separated by a 10-foot dividing strip to be planted with grass. At such points on the long, easy curves as approaching headlights might cross, the strip will have screening of shrubbery.
Outside of each lane is a 10-foot shoulder, level'with the concrete and surfaced. Only in the cuts—such as the great Clear Ridge cut near Everett, which is 153 feet deep at centre Me, 394 feet wide at the top and half a mile long—do these hard shoulders narrow to seven feet, with a three-foot drainage ditch.
The driver who makes the sudden transition from such construction to the typical "black-top" winding mountain road, with its rough shoulder edge and ofttimes soft margin, gets an unforgettable object lesson in kow important to safety the detail of shoulder design can be.
Text read from the printed page and cleaned; old type leaves the occasional error.