Work package 5 of the IMAGINE project deals with Road noise sources and has the task "to provide default databases for the source description of road noise, i.e. vehicle category and possibly road surface type related, for a typical fleet of European road traffic, and provide guidelines on how to deal with situations deviating from the default value". Based on the data gathered in the Harmonoise project a first model has been made, which distinguishes two sources: rolling noise and propulsion noise. Both sources are described showing dependency on vehicle speed and vehicle class. Various correction factors are introduced, of which the most important are the road surface and vehicle acceleration. Within the framework of Imagine various extra sources of information have been gathered in order to improve the model. The most important results are: o Measurements on powered two wheelers. Both on board measurements and statistical passby measurements have been performed resulting in a first estimate of the model parameters. o Detailed measurements on a truck in a semi anechoic chamber. Resulting in detailed spectral information on the behaviour of the powertrain. Additional measurements were performed during driving up- and downhill. o Measurements on accelerating traffic. Statistical pass-by measurements where performed on traffic accelerating from a roundabout while measuring vehicle speed and acceleration. These insights will be used to tune the acceleration coefficient in the model o Statistical data on vehicles fleet composition. Various sources have been found for information on the national differences in fleet composition in Europe. These data will be used to determine national correction factors from the "universal European model". An action plan has been set up in order to answer the remaining questions by additional measurements, analysis and data gathering. A summary of the remaining issues and remaining work items is given in Table VII in Chapter 5 of this report.