State highway and transportation agencies throughout the United States are faced with the task of implementing the most cost-effective vegetation control strategy to save scarce maintenance funds. Reported in this paper are the findings of a study that investigated the costs of two primary vegetation control strategies being tried in Texas. These strategies are (a) increased use of contract mowing and(b) increased use of chemical overspraying. The costs used in the evaluation of each strategy include direct charges such as labour plus fringe benefits, equipment rental, and materials and also indirect or overhead charges that include administrative, office space rental, and warehouse and shop rental. A least squares regression analysis of sample data reveals the primary factors that affect the two vegetation control strategies: the number of vegetation inventory acres, number of full-width cycles, location (urban/rural and or vegetation areas), and the amount spent on contract mowing, in-house mowing, or herbicide overspraying, or all three. The results of the study reveal that contract mowing is considerably more cost-effective than in-house mowing. On the other hand, chemical overspraying is more cost-effective than mechanical mowing. Such findings lead the analyst to conclude that chemical overspraying supplemented with a minimal amount of contract mowing is the best vegetation control strategy to implement.
Abstract