The objective of this project is to collect and deliver high quality road data primarily for the development of performance prediction models. The monitoring of the LTPP sections started in 1984 on commission of the Swedish Road Administration. The aim is primarily to focus on road deterioration caused by heavy traffic. The project started with a limited amount of sections but the number, both active and inactive, has increased to 655 sections distributed over 66 sites. Budget restrictions in 2000 resulted in a decrease in monitoring by 25 per cent. In 2008 there were still 331 active LTPP sections distributed over 35 sites. Road data from this project has been used in the development of flexible pavement models for predicting the cumulative number of load applications to the initiation of cracking and for predicting crack propagation. Crack initiation was defined as the first appearance of cracking in the wheel paths.