Samenvatting
The number of vehicles with which radio communication can be established is increasing. It may consist of a two-dimensional link with transmitter and receiver or a single-directional link between a broadcasting station and the radio receiver on board. These links are generally carried out in VHF or UHF. Such a system doesn't work however in tunnels. Therefore two other systems are available. Probably it will be necessary to use all three for road networks. Discussion is added.