Agencies have collected data for pavement management for many years now. These data have been used primarily to develop short- and long-range rehabilitation programs. Another valuable use of these data is improvements to engineering procedures. The Illinois Pavement Feedback System (IPFS) is a comprehensive inventory and monitoring system that was designed in 1984 to provide data for both programming and engineering uses. Over the past 10 years many engineering issues have been addressed through the use of these data. IPFS data were used to provide feedback to designers and administrators on the design of new (or original) pavements and on overlay designs. Results from a survival analysis of thousands of kilometers of original jointed reinforced concrete pavement (JRCP), continuously reinforced concrete pavement and hot-mix asphalt concrete pavements and asphalt concrete (AC) overlays of these pavements were used. Key results relate to performance variability (a wide range of performance was found for identical designs) and thus the need for a design reliability greater than 50 percent, the expected pavement in-service life in terms of both age and traffic [equivalent single axle loads (ESALs)] of each pavement type and overlays (for example, the mean life of JRCP was 24.1 years and 16.6 million ESALs and the mean life of the first thick AC overlay was 14.5 years and 23 million ESALs), the effect of overlay design thickness, and the effect of concrete material durability (D cracking reduced ESALs carried by 50 percent).