AbstractRutting in roads is an important factor that affects the performance of a road. A model used to predict future rutting for different design alternatives is important to minimise the investment cost and LCC.In the project “Pavement Performance Models: Part 2, Project Level”, a new road design model, especially used to predict future rutting, has been developed and validated. Together with the European test method, EN 13286-7:2004, and some other standardised test methods, this model has been validated to the actual rutting of eight 10 – 20 year old LTTP roads.During this validation there have been some interesting findings:•The “Shakedown Theory” is valid for real roads, not only for triaxial tests and test roads.•There is a strong connection between rutting, roughness and cracking in these roads.•The most important factor that contributes to rutting in a road is the shear stress level.•It is possible to accurately predict the rutting on a road, if the stress level does not exceed the “Plastic Shakedown Limit”.•With this knowledge it is possible to use a better design method during the whole process.•It is also possible to predict the performance of a road, which should be built with local and/or recycled material, which is not accepted or described in the standard of the country.