Variability and Control of Gravel Road Visual Assessments

Annual visual assessments form the backbone of the Gravel Road Management System operated by the Provincial Government of the Western Cape in South Africa. Information is used to identify, quantify, and prioritize periodic maintenance activities; to describe the condition of individual roads and road networks; and to monitor their performance. The current assessment methodology is well described and has been applied for over 10 years. Although assessors are well trained and calibrated through regular formalized training sessions, inconsistencies still occur, which result in some variability of the final results. Efforts have been made to identify shortcomings in the assessment methodology, training, and quality control process. Duplicate assessments carried out each year on 10% of the road network were analyzed for this purpose, as were assessments of selected road sections carried out by all assessors during the annual training sessions. The assessment methodology and quality control process are discussed briefly, and the results of the study to improve the quality of visual assessments for network-level road management are highlighted.