Establishing Safety-Based Minimal Pavement Performance Thresholds to Support Municipal Infrastructure Asset Management

Road asset management agencies, including transportation units in a municipal setting, must ensure that the roads are safe for the public. To do so, one must translate this safety requirement to a set of minimum pavement condition thresholds. Roads that fall below these thresholds should be regarded as failed and must be immediately repaired. So far, determining safety-based thresholds has primarily relied on extensive accident data analysis, which presents challenges for municipal infrastructure agencies lacking such data. To bridge this gap, the study proposes a practical method for determining safety-significant pavement performance thresholds. These thresholds consider road class owing to different design speeds. It begins by identifying safety-sensitive distresses and then reviews their critical thresholds at different speeds. The proposed method is illustrated using the City of Calgary’s pavement assessment practices. Results indicate that low-speed roads should prioritize addressing potholes and rutting, while high-speed roads should focus on mitigating roughness-related safety risks. Additionally, there is no one-to-one relationship between the overall pavement performance index and individual distress, and the overall performance thresholds established in this study should be considered conservative. The findings provide valuable references and insights for municipal road asset management, and the proposed approach can be applicable to other municipalities and provincial transportation agencies or state departments of transportation.