Speed limits have been established for the good of the motoring public, primarily for purposes of safety. A study has shown that by reducing the number of violators on freeways, the resulting more uniform speeds contribute to improved capacity and safety (22). The effectiveness of a speed limit on a facility depends on the degree of enforcement and public support (3,4). The public will support and obey speed limits that are safe and reasonable; however, speed limits that are illogically restrictive cannot be enforced except by tremendous effort and expense, and then usually not for 1 ong (3). It is the duty of traffic engineers to establish speed limits by careful investigation and evaluation. The most commonly used method of establishing speed limits is to take the 85th percentile of the observed speeds (32,26). J. C. Oppenlander suggests another method of establishing the best operating speed by optimizing the three resources expended in highway transportation: the economics of vehicle operation, the value of time, and the safety of travel (33). Driver Characteristics The speed a driver chooses is dependent upon his desires and environment; therefore, speed control is difficult because of variations in the driving behavior of individuals (3,22).

No abstract