Estimation of Norwegian Asphalt Surfacing Lifetimes Using Survival Analysis Coupled with Road Spatial Data

Combinations of different factors and their relative importance have a mixed effect on the longevity of pavements, which are essential to be understood to enhance long-term maintenance planning. This study used spatial road data from Norway followed by integrating temporal-spatial and statistical analyses to show a potential approach to estimate the lifetimes of asphalt surfacing. For the statistical part, a stratified Cox proportional hazard model was used to understand the relationship between longevity of surface mixtures and different factors, while avoiding having predefined assumptions rooted in deterministic modeling. In addition, rutting was used as the response variable to determine distress-specific asphalt surfacing lifetimes and to handle censored data. Inclusion of rutting as the response variable showed that the median technical lifetime of asphalt surfacing is about 2years shorter than that of the maintenance activity records. The results showed the significance of each covariate; however, aggregate nominal maximum size and heavy traffic volume were consistently the significant covariates across the studied traffic classes. In addition, the results were fitted to reference categories in each covariate to show a practical approach to interpret absolute values of lifetimes from a survival table.