Method and system for speed verification

The invention relates to a method for verifying the speed of a vehicle A among a number of vehicles adapted to communicating with one another by V2V (vehicle-to-vehicle) communication or to communicating between vehicle and infrastructure by V2I (vehicle-to-infrastructure) communication, which method comprises monitoring vehicle A's speed and generating a speed signal V A which presents the vehicle's speed, generating a reference signal S ref which contains information about the speed of at least one other vehicle B, verifying vehicle A's speed based on said speed signal V A and reference signal S ref and generating on the basis thereof a verification signal S v . The invention relates also to a system for verifying the speed of a vehicle A.