Evaluating a pavement's structural capacity involves analyzing deflections measured by Falling Weight Deflectometer (FWD) while assessing surface roughness, estimated from longitudinal profile measurements, helps determine its functional performance. However, seasonal and diurnal changes (temperature and moisture) influence such measurements. Evaluating temporal variations and quantifying their impact on these measurements may aid in a better understanding of pavement parameters derived from these measurements. Long-Term Pavement Performance (LTPP) Seasonal Monitoring Program (SMP) study is designed to understand environmental factors and their effects on pavement structural and functional performance. Analyzing data from the SMP study shows that FWD and profile measurement season and time of the day have a significant impact on parameters derived from these measurements. Relating the observed effects with recorded ambient temperatures helped developing general guidelines for FWD and profile measurements in different climatic regions.The recommended temperature range for FWD testing on rigid and flexible pavements in freeze climates is 55 to 70oF; 65 to 75oF and 60 to 75oF in the non-freeze climates for flexible and rigid pavements, respectively. The study recommends before-noon FWD testing for rigid, while no time limit within a day for the flexible pavements. Also, the research suggests a temperature range between 50 to 75oF for flexible pavement profiles with no time limitation. For rigid pavements, profile measurements in the afternoon are recommended with temperature ranges of 50 to 65oF, and 50 to 70oF in freeze and non-freeze climates, respectively.
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