Traveler Information > En-route Driver Info > Highway Advisory Radio

What Is It?

Highway Advisory Radio (HAR) is one of the oldest traveler information technologies, along with variable message signs and commercial radio traffic reporting. HAR was first used in 1940 on the George Washington Bridge in New York City. See our Telecommunications Diagram on HAR for more information.

Its broadcast range usually falls within one to six miles, and nearly all HAR systems use the AM band. According to federal regulations, HAR broadcasts may not contain entertainment or commercial messages. They are often used in conjunction with variable message signs, which will tell drivers where or when to tune to HAR.

Highway advisory radio broadcasts inform travelers of:

• detours;
• operating restrictions such as requirements to put on snow tires or chains;
• warnings about hazards such as forest fires, floods, mudslides or highway closures;
• traffic conditions along short segments of specific routes, especially work zones;
• directions to tourist attractions;
• parking availability;
• public transit alternatives; and
• notices of events.

Key Results

Evaluations show that travelers are unlikely to switch off their music or other entertainment to listen to traffic information reports, which have a reputation for being repetitious or out of date. Those who do tune in express high levels of satisfaction. Travelers have demonstrated more interest in radio broadcasts about specific locales or specific weather conditions.

Benefits

A highway advisory radio broadcast can include more specific information than a commercial traffic report or a variable message sign. Its other advantage over commercial broadcasts is that it can be available 24 hours a day. No additional equipment is needed to receive highway advisory radio broadcasts since most cars have AM radios.

Costs

Keeping the information current is labor-intensive. Under some conditions, placing, installing and maintaining antennas can be costly, as can staffing and equipping a central control facility to coordinate information from multiple agencies.

Implementation Challenges

• making travelers aware of the service because frequencies change so often and cover such small territories;
• designing the message, which must be succinct yet comprehensive; and
• maintaining AM signals at a quality that is enjoyable to listen to

Where is it Implemented?

Many turnpikes, toll facilities (tunnels, bridges) and other “closed” systems such as airports, causeways and national parks use HAR. It is also used to broadcast changing conditions in long-term construction sites that have a large share of repeat visitors. In Europe primarily, a variation of HAR is used to broadcast to on-board receivers messages that are customized according to the vehicle's location. As Internet-ready digital cellular transceivers become standard options in new vehicles in the U.S., there may be a way to tie them in to a Web-based radio communications system.

Author: Phyllis Orrick