Estimating road management equipment inventory needs and associated purchase costs

This paper presents a method for estimating road management equipment inventory needs and associated purchase costs. The primary feature of this method is to consider historical operations records by road management equipment type and weights by work type based on subjective preferences of the public agencies. The Analytical Hierarchy Process (AHP) is employed as the main tool to reflect the relative importance of a day-to-day road management activity. In order to examine the appropriateness of our method, we performed a case study with 18 regional transportation offices in South Korea. The estimated cost of equipment purchases across these offices was approximately 41 million US dollars based on the 2011 year (when apply average unit cost by equipment), while the actual equipment purchase costs during the same one-year period were about 44 million US dollars. The main reason for the differences of estimates across offices is due to unit cost by equipment, road conditions, relative importance of management tasks, and omission of unused equipment in inventories and use of labor. We also developed estimates using the maximum unit costs by equipment, in order to provide an upper bound to the authorities. Using those values we estimated the annual cost at approximately 60 million dollars. The estimates developed can provide useful information to road authorities when they establish annual plans for road management.