The objective of this project is to collect and deliver high quality road data primarily for development of performance prediction models. The monitoring of LTPP-sections started in 1984 on commission of the Swedish Road Administration. The aim is primarily focused on road deterioration caused by heavy traffic. The project started with a limited amount of sections but the number of sections has increased to 655 sections distributed over 66 sites, still active and inactive, in year 2007. Of budget reasons an overview resulted in a decrease of monitoring sections with 25 %. In the year 2007 there were still 345 active LTPP-sections distributed over 36 sites. Road data from this project has been used for developing models for predicting the cumulative number of load applications to the initiation of cracking for flexible pavements and to develop models for predicting crack propagation in flexible pavements. Crack initiation was defined as the first appearance of cracking in the wheel paths.