Determine the relationship between ride quality and structural adequacy using the Long-Term Pavement Performance (LTPP) and other pavement performance databases. This proposal essentially addresses unfinished business from the original American Association of State Highway Officials (predecessor of the American Association of State Highway and Transportation Officials) Road test, which developed all the initial "ratings" and relationships between ride and distress; however, the loadings were only over two years (accelerated), the traffic was relatively light compared to today's standards, and the test sections were very short to measure ride. Initial efforts in network pavement management systems concentrated on the evaluation of visual distress survey data only. It is also important to include ride quality and some evaluation of the structural integrity of the pavement and subgrade. The public measure of ride and the engineering value of structural support will provide a more complete view of the roadway system, which is needed for network-level resource allocation. The research will identify a relationship between ride and structural support, or establish ride deterioration as an indicator of structural adequacy for use in pavement management as an additional surrogate for structure. In either case, the network pavement management can then account for all condition data in both resource allocation and the performance models employed. This will provide information as highway agencies implement new pavement design procedures. The Road Maps for Asphalt, Concrete, and Preservation indicate that there is limited research that attempts to relate pavement smoothness (both initial and long term) to pavement performance. Selection of individual treatments and the materials used in those treatments impact various performance characteristics, including structural integrity as well as functional characteristics such as noise, friction/skid resistance, and smoothness. Research will provide information allowing highway agencies to evaluate the full performance impacts of preservation treatments as well as cost in the treatment selection process. The increased damage to pavements resulting from dynamic truck loads on rough roads may be significant in terms of pavement life. This relationship needs to be quantified so pavement engineers understand the functional and structural performance of various solutions over time, as the data from many studies are sufficient to examine the relationships between structural support, smoothness, friction, noise, moisture beneath the slab, drainage, and other factors. Previous work related to this topic has included the National Cooperative Highway Research Program 20-50(8/13), Factors Affecting Pavement Smoothness (Objective 7B); the Federal Highway Administration/Long-Term Pavement Performance reports on evaluating load transfer or Portland cement concrete-jointed pavements; and the Federal Highway Administration/Long-Term Pavement Performance reports on profile devices. Three other reports, FHWA-RD-99-074, FHWA-RD-00-113, and FHWA-RD-00-076, considered the data variability of distress, profile, and faulting data. None of these reports evaluated the relationship between functional and structural pavement measures. This activity and the ongoing National Cooperative Highway Research Program 01-45, Models for Estimating the Effects of Pavement Condition on Vehicle Operating Costs, will help to address the gap to "document the benefits of pavement smoothness relative to performance and user satisfaction."
The key project objective is to identify and verify the relationship between ride quality and structural support or ride deterioration and structural adequacy to improve evaluation and use of pavement condition data in pavement rehabilitation and design decisions.