Sampling Procedure for Performance-Based Road Maintenance Evaluations

Maintaining the road infrastructure at a high level of condition with generally limited amounts of available funding is a challenge for many transportation agencies. To address this challenge, many road administrators worldwide have implemented performance-based maintenance contracts. In performance-based maintenance contracts, road administrators define performance measures (e.g., performance-based specifications) that specify the minimum condition at which the asset items are to be maintained. To ensure that contractors maintain the asset items according to these measures, road administrators must design and implement a comprehensive and reliable performance monitoring process. One of the most important areas within the performance monitoring process is inspection conducted in the field. Defining a procedure that guarantees the success of field inspections is a challenge. When defining such a procedure, road administrators must consider budget and time limitations, among others. Since performance-based road maintenance contracts are relatively new, the availability of guidelines for such issues (with focus on performance-based contracts) is limited. That need is addressed by presentation of a three-stage and seven-step statistical sampling procedure developed to ensure that findings from field inspections will be reliable and representative with high confidence of the actual condition of asset items in the entire population. Also presented are three alternative approaches for sampling for the cases in which sampling needs to be performed not just once but multiple times over the duration of a performance-based road maintenance contract.