An Intelligent Transportation Systems (ITS) device is described. The ITS device (400) includes: radio resources including a receiver (402) adapted to receive a radio signal in at least two frequency bands; a channel detector (410) arranged to analyse a signal received in a first frequency band to determine the presence of a transmission in that frequency band; a controller (402) configured to control assignment of radio resources, and in the event that the channel detector detects a signal in the first frequency band, to prevent transmission of a potentially interfering radio signal. The first frequency channel can be part of another radio communications system, such as a RTTT1 SSRC radio system.