This project is part of the Swedish IVSS program. The aim of IVSS is to stimulate research and development of the future road safety. Road conditions with low friction have been identified as a frequent cause of traffic accidents. Therefore, technology to automatically detect changes in road conditions and alert the driver or take proper actions with active driver support systems would be a key contribution to increased road safety. This project is a continuation of a previous project and aims at further developing the road friction estimator and creating methods for evaluation of such. An investigation was conducted of relevant measures for estimation of the coefficient of friction, resulting in a number of measures. With these measures as a starting point the three methods, from the previous project, based on longitudinal and lateral tire forces and optical properties, were further developed. Both separately and in combination with each other. For an industrialization to be possible the sensors need to work properly but they also need an end user, hence new and existing applications which could incorporate a friction estimate were suggested and evaluated in the aspect of the above measures. The three methods separately and in combination have been successfully evaluated, using the developed evaluation method, at proving ground and public road tests in summer and winter conditions with different tires.