Simulation has become a useful tool for vehicle manufacturers in the design and assessment of new vehicles. Using an advanced driving simulator in early design phases may reveal defects in the construction, which otherwise would not be noticed until full scale prototyping, and thereby reduce development time and costs. In most driving simulator studies the road design does not have to conform to an existing road. But for some purposes it may be crucial that the virtual road describes the real road as close as technically possible. Examples are vehicle vibration studies, fuel consumption evaluation with respect to driver behaviour, and comparisons between driving on the virtual and real road. The required level of detail of different road features varies between applications (projects). Parameters like road curvature, inclination, elevation and crossfall, the surrounding terrain as well as road imperfections and unevenness may be of more or less importance and therefore have to be modelled with high or lower accuracy. In the Known Roads project, a real road, the “Gothenburg triangle” (Gothenburg-Borås-Alingsås- Gothenburg), was modelled as realistically as possible. Road curvature, inclination and crossfall as well as the surrounding terrain were considered important. This White Paper is complementary to other deliverables from the Known Roads project. It presents in more detail the method of recreating existing roads in a simulation environment, developed by VTI in the project. The White Paper concerns specifically the difficulties of merging different data sources into a road representation, and describes the problems that were encountered and the solutions that were developed for implementing an existing road in the driving simulator.