The FAMAROW Model: Estimating Marginal Contribution to Road Wear Costs on In-service Roads
H M Hjelle, Molde University College, NO
Traditionally the estimation of marginal road wear costs has been based on either experimental data (e.g. the AASHO Road Test, or laboratory tests) or mechanistic-empirical models for the interaction between vehicles and the road construction. The problem with these experimental data is mainly that they may not be based on representative environments with respect to traffic characteristics, road constructions and climatic factors. In order to investigate this potential problem, there is a need for alternative approaches to estimating marginal road wear that can enable methodological 'triangulation' in this complex field of research.
This project, which is a part of an PhD dissertation, represents a first effort of relating Weigh-In-Motion(WIM) data collected on in-service roads, reflecting factual traffic compositions to factual measured road wear data (rutting and roughness). The data is collected over a 11 year period on more than 50 locations on in-service national roads in Norway. The observation sites are originally designed for automatic traffic (speed) surveillance, but the piezo-electric sensors can also serve as a crude form of WIM-sensors.
Corresponding measurements of rut-depths and roughness has been carried out by laser and ultrasoundequipped vans over the same period, providing time-series data sets that could be used for estimating the factual contribution to road wear by different vehicle types.
A statistical model (FAMAROW) is developed, and a first effort has been made to estimate the vehicles' marginal contribution to road wear using this model.
Finally the results are converted into economic figures that could be entered into models for calculating road user charges.
Association for European Transport