Citation

Saal CC. Highw. Res. Board bull. 1955; 107: 1-35.

Copyright

(Copyright © 1955, National Research Council (U.S.A.), Highway Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Instruments developed by the committee on vehicle characteristics of the highway research board were used to observe certain operating characteristics of a typical 1951-model passenger car. These instruments record for any trip the amount of time in seconds that a vehicle operates in various class intervals of speed, rate of deceleration, percentage of maximum intake manifold vacuum, and percentage of throttle opening. The total trip time and amount of fuel consumed in each class interval of speed are recorded, making it possible to compute the average rate of speed and fuel consumption. The typical passenger car was operated by the same test driver over about 28,000 miles on various turnpikes and parallel major highways to determine the advantages with respect to vehicle operation that may result through the use of freeways instead of the parallel major highways and to show to what extent certain built-in characteristics of the vehicle are used in normal operation. Other studies evaluated the effect of traffic signals, sight distance, grade separation and traffic conditions on certain operation characteristics of the vehicle. Special tests were conducted with other instruments to determine the fuel consumption and accelerating ability on individual grades. A considerable time saving was revealed from use of the freeway by comparison between travel time on the freeway and on the parallel highway. Measured fuel consumption indicated that the use of the freeway resulted in a higher rate of fuel consumption for the test car. Use of the freeways saved enough travel mileage to make the fuel consumption in gallons approximately the same for an average trip over either type of facility. no more than 60% of the maximum decelerating energy of the test car was used on any test model, and the maximum engine torque and full throttle opening were used only for an insignificant part of the time