The road network is a key resource of enormous value for the society. The maintenance, planning and construction of the road network is highly dependent of accurate traffic figures. It is also necessary to have traffic figures that cover all parts of the road network. In Norway the road network have a total length of 90000 km. The Norwegian Public Road Administration (NPRA) has a program which counts vehicles in the whole road network. There are over 9000 counting station sites in the road network. The NPRA use ground based sensors, radar, or stationary cameras to monitor the traffic. The sensors count the number of vehicles that pass a given point over time. The traffic counts are used to estimate traffic parameters like AADT (annual average daily traffic). The counting program does not have enough resources to keep every station in operation every year. On average each counting station operates every 4 years. Despite the great number of counting stations there are many parts of the roads that are not monitored at all. The equipment is expensive to purchase and operate, and the methodology has evident shortcomings due to the very limited geographical coverage of the system. The NPRA experiences great demand from the environment authorities to increase the amount of traffic monitoring. The counting program consists of short time counting stations (8700) and continuous stations (500). The continuous stations count traffic every hour and every day year after year. These stations also classify the traffic in length groups and measure speed. Very high resolution satellite imagery may provide an important contribution to the traditional ground-based system. The spatial coverage offered by satellite images is much greater than can be achieved from ground-based sensors. However, the temporal resolution offered by high resolution optical satellites is low. Therefore, satellite data should be used in combination with data from the continuous counting stations. This is the background for the cooperation between NPRA and NR (Norwegian Computing center) in the satellite traffic data project (SatTraffic).