ASPECTS OF PERFORMANCE OF TRUCK WEIGH STATIONS

The performance characteristics of truck weigh stations are presented. Seasonally operated scales and random inspection sites are found to b e at least 3 and 8 times respectively as effective in detecting violat ions as continuously operated permanent scales with no alternative byp ass routes. The availability of alternative bypass routes reduces truc kers' perceived probabiIity of detection at permanent weigh scales by at least 5%. Higher perceived probabilities are associated with high i nspection rates. Queuing theory is employed to study the impact of two alternative manpower levels on the performance of continuously operat ed permanent weigh scales. For the level of truck traffic volume consi dered, it is found that, theoretically, there is no significant delay to truck traffic through such weigh scale stations irrespective of the manning strategy. It is concluded that it is feasible to maintain min imal staff at the scales and redirect human resources to increase insp ection capacities of other methods. The queuing model for the permanen t scale operations represents a rare practical example of a classic M/ E(k)/1 model where the k stages in the service time Erlang distributio n are real and not necessarily imaginary.