Acceptable International Roughness Index Thresholds based on Present Serviceability Rating

摘要

Each State is required to report their annual roadway International Roughness Indices (IRI) to the Federal Highway Administration (FHWA) since the early 1990s. The Highway Performance Monitoring System (HPMS), has resulted in the development of a database for monitoring the national roadway systems on a biennial basis. The reported IRIs for each state are compared with the national standard to identify road segments that need to be included in the repair or maintenance programs of each jurisdiction. The national standard in the United States for IRI thresholds for all road classifications range from 96 in/mi to 170 in/mi indicating "acceptable" road segments, and IRI less than 95 in/mi are considered to be "good" road segments. However, several states are reviewing their strategic repair and rehabilitation programs based on IRI values for previously identified road sections using IRI. The consensus is that the national standards for IRI may not reflect the general perception of pavement smoothness by road users in each jurisdiction. This research is aimed at obtaining a perception of roadway smoothness based on field surveys. Acceptable IRI thresholds were developed based on the correlation between the perception of ride quality and IRI values, with inferences at 95% confidence interval.