Road Network Operations
& Intelligent Transport Systems
A guide for practitioners!

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This webpage is best read in conjunction with advice on use of radio and television for trip planning. (See TV & Radio )

En-route Traffic and Travel information delivered by Radio can be broken down into the following sub-groups:

  • Highway Advisory Radio (dedicated radio stations)
  • Traffic/Travel Radio Bulletins (digital or analogue) as segments within wider radio programming

Highway Advisory Radio are dedicated, usually local, radio stations broadcasting traffic and travel information and information on points of interest. Very often the traveller is advised of these services by the use of static signs next to the Highway network. Such services are common in the USA. In the USA these Traveller Information Systems are licenced by the Federal Communications Commission and are generally low power AM stations. Elsewhere they are also used in Japan along major motorways (AM). In Italy and France similar services operate (FM). In the UK (England), the Highways Agency has experimented with both low power AM Highway Advisory Radio services for specific major events and also a full internet radio service. However these services have now been discontinued.

Internet Radio traffic and travel specific services are also used. The UK’s Traffic Scotland service provides an Internet radio service covering Scotland with a looped travel information broadcast. A National (all Scotland) broadcast is updated every 20 minutes at peak times and every 30 minutes at off peak times and regional Scottish content is updated every 30 minutes at peak times and hourly at other times.

Highway Advisory Radio provides an effective way of informing motorists of problems on their current route where static signage informs the driver of the frequency they need to tune their receiver too. A research report from CalTrans in the USA presents technical information and insight into factors to consider when locating AM Highway Advisory Radio transmitters.

Traffic and Travel radio bulletins, as discussed in the pre-trip section provides tailored traffic information in short bursts within other programming. The level of detail provided and relevance will depend in part on the target audience and geographic coverage of the radio station. Necessarily the wider the radio station coverage area the more selective the incidents presented must be and therefore the classification and selection of the incidents for broadcast is significant.

Broadcasts are often focused on ‘Drive Time’ associated with commuter peaks. Incident information presented should be short and clear with some descriptive detail, some impact assessment and if possible, some resulting travel advice. The message should be broadly consistent with other information channel outputs.

Reference sources

CalTrans (2011) Improving Highway Advisory Radio Predictability and Performance. Caltrans Division of Research and Innovation. Available for download at: