Citation

Eckhardt PK, Flanagan JC. Highw. Res. Board bull. 1956; 120: 1-5.

Copyright

(Copyright © 1956, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

A few of the results are presented from a 2-year study of accident causation on the Pennsylvania Turnpike, data from which serve as a barometer indicating how well the roadway in modern high speed highway design is working. The curve and grade elements are discussed from the standpoint of the accident rate and the vehicle involvement rate. The broad combinations of curves and grades are tabulated against the percentage of accidents for each combination. The combinations considered are straight and level, straight and upgrade, straight and downgrade, curved level, curved upgrade, and curved downgrade. The large number of critical incidents or the actions that led to the accidents were classified into nine broad driver-behavior groups. Certain groups of incidents which showed a statistically significant relationship to certain of the six road course combinations are indicated. The total number of vehicles which used the pike and the vehicle miles of exposure were used to establish a perspective of the real boundaries encompassing the data used in the foregoing discussions. The data indicate that the modern design is working well. It is strongly indicated that in this man-machine-roadway system, the roadway design is ahead of the man-machine part of the system. Two courses of action are briefly stated in conclusion and mention is made of the challenge which the statistically significant relationships between accidents and road course present to the designer.