Satellites and satellite devices are not available everywhere so digital radio can be a very good and efficient alternative. So, DRM services in the FM band are the most efficient way to cover a string of highways with the least possible number of transmitters. Thanks to its SFN capability (Single Frequency Networking) DRM can broadcast DRM signals in both directions from a single transmitter (while analogue FM services in ‘synchronous mode’ can only transmit into a single direction from each transmitter site). Plus, DRM requires less signal power for perfect reception of the digital signals, thus extending the distance between transmitter sites even further. Those highway transmitters using DRM in the FM band can carry more than a single analogue audio service (as an FM based transmitter network would),  but rather up to 3 audio services plus a Journaline text application per DRM transmission. DRM transmissions can carry more than audio services as in traffic other information than just audio is vital.