The thesis deals with cooperative traffic information systems, which support the driver of a car in selecting a route, based on traffic information collected by other cars. System participants contribute measurements of the traffic situation in their vicinity (e.g., current traffic flow speed) and use the measurements made by other drivers to find the fastest route to their destination with regard to the current conditions. Such systems help avoid traffic jams, highly congested roads, and other deterioration. The communication pattern of the discussed application is quite challenging: continuously updated data (i.e., description of the current traffic conditions) are to be made available to multiple participants spread over relatively large geographical areas. Cooperative traffic information systems have primarily been discussed in the context of direct, ad-hoc communication between cars. We formally show in this thesis that a very special communication properties of the discussed application do not fit into the constrained capacity offered by mobile ad-hoc networks. Consequently, this work proposes an alternative design, based on a peer-to-peer paradigm and cellular networks.