Highway Advisory Radio
A real-time highway advisory radio (HAR) system will be used to provide traffic information to the traveling public through the vehicle radio.
HAR ranges vary considerably depending on terrain and other factors. The nominal range of the HAR equipment is 2.5 miles.
Within this range motorists can tune their radio and listen to a one to two minute message at least once, even at highway speeds.
Transportation departments use HAR for informing motorists of the following:
- Traffic hazards
- Dangerous driving conditions
- Motor vehicle laws
HAR operational guidelines are as follows:
- Operators should know the message status of HAR at all times.
- Operators should avoid using a monotone voice when recording a HAR message.
- When no current incident information is being broadcast, construction advisory information that will affect motorists in the corridor should be broadcast.
- Unless reliable, real-time traffic condition information is available on alternate routes, specific alternates should not be suggested.
- HAR operating agencies should be willing to air both major construction and incident information for other agencies.
- Flashing lights are activated for a traffic advisory message, only information on the incident should be included in the message.
- No incident information should be broadcast until the information has been verified.
- No message should be broadcast stating that an incident has been cleared. Instead, the incident message should be deleted from the playlist. However, in a corridor system, an update should be provided.
- A flashing light, traffic advisory message should be updated at least once an hour.
HAR message content should include:
- Station and Facility Identification
- Route, location (exit number, cross street, and township), and direction. When a route may be known by a route number and a name, i.e., I-495 (Long Island Expressway), both should be used.
- Type of incident; conditions of delay
- Day and time of recording