The transportation system consists of road, rail, sea and air infrastructures. It includes the possibilities and limitations of its economics, laws and regulations, which sets barriers to the capabilities of an individual and mass motorist. For instance, speed can be influenced by method of travel (vehicle, airplane, train or ship), by financial capabilities for the type of vehicle (jet versus commercial, speed boat against sail boat and sedan compared to a luxury sports car), or by regulations such as speed limits in rural areas versus city driving.