In the last few years, there have been rapid developments and advances oftechnologies for pavement cracking surveys for both data acquisition and data interpretation. This paper discusses the basic hardware and softwaretechnologies used for developing the Automated Distress Analyzer (ADA), and experiences of ADA field applications. At this time, ADA is essentially cracking software program for automatically identifying cracks, and their locations and geometries. The paper attempts to present the status of developments, such as laser based imaging with low power consumption and shadow-free characteristics, and real-time and fully automated analysis. In particular, the paper presents data evaluations of ADA results based on three cracking indexing protocols: the Crack Indicator (CI) proposed by BillPatterson of World Bank, the AASHTO Interim Protocol used in US, and the UK SCANNER method adopted in many European countries. Another emphasis ofthe paper is on the usage of cracking protocols and influencing factors that may pose substantial limitations on some of the currently proposed protocols that were designed to handle automated cracking systems. One conclusion from the analysis is that at this time a simpler cracking protocol needs to be considered for deployment. This simple protocol should be easily extended in the future to incorporate information on load-associated cracks and other information when technology has improved and become mature enough. Specific advantages of UK SCANNER protocol are discussed along with the applicability of protocols in relations to project level and network level surveys.
Abstract