Traffic safety lighting on the Pennsylvania Turnpike

FOUR types of illuminants-high-intensity mercury-vapor, sodium-vapor, fluorescent, and incandescent-are used for various types of lighting applications on the new Pennsylvania Turnpike which recently was opened to traffic. First important “super highway” in America, the new turnpike stretches 162 miles between Pittsburgh and Harrisburg, Pa., burrowing through the highest ridges of the Allegheny Mountains with seven mile-long tunnels. More than 110 miles of the four-lane road is straight, the maximum grade is three per cent, and the worst curve is six degrees.