In 2006, the Ministry of Transportation of Ontario, Canada (MTO), completed a study with the Centre for Pavement and Transportation Technology at the University of Waterloo to evaluate the performance of automated and semiautomated technologies that collect pavement distress data. From that study it was recommended that MTO define concise guidelines for surveying pavement distresses at the network level by using automated collection technologies and semiautomated distress analysis and for the guidelines to give special attention to quality assurance. In light of that recommendation, the study detailed in this paper presents the development of pavement distress guidelines and a distress manifestation index (DMI) for network-level (DMINL) evaluations by using automated collection technologies and semiautomated distress analysis. To define and validate DMINL, sections evaluated in the previous study were considered. The relative effect of each distress was obtained by linear regression and statistical analysis. The principle used to define the weighting factors was that the distresses considered by the new guidelines should quantify with a minimum error the DMI estimated by the MTO traditional method.