Choosing an Inventory Data Collection System

As part of NCHRP Project 15-15, Collection and Presentation of Roadway Inventory Data, the authors conducted a nationwide survey of the state departments of transportation (DOTs), visited several DOTs and vendors, and reviewed the literature regarding roadway inventory data collection. On the basis of that work, a process to help state DOTs match inventory needs to data collection technologies is presented. The process that is described may help state DOTs narrow their focuses to the most relevant inventory data collection technologies. The authors present a four-step process that can be used to select inventory data collection technologies. First, the authors help agencies view their inventory data collection in context. The authors show how successful inventory data collection in the past has focused on the provision of timely information that is used to solve problems. Second, inventory units must select the proper mode of transport for the data collection technologies. Units should consider vans, the popular choice, versus satellites at one extreme and backpacks at the other extreme. Next, inventory units need to select the georeferencing technology. The relative merits of global positioning systems, inertial navigation systems, distance-measuring instruments, and range finders are discussed. Finally, inventory units must select sensors to provide descriptive information. For each common inventory element, the authors estimate the accuracy of collection with six common technologies and other special techniques. The authors also describe the initial costs and labor needed for the different collection technologies.