Abstract: A traffic information warning system for conveying traffic information from a traffic advisory site to a vehicle is disclosed. The traffic warning site comprises an emergency vehicle, a roadside hazard, or the like. The system comprises a transmitter adapted for placement at the advisory site and a receiver adapted for placement at the vehicle. The transmitter includes a first oscillator for transmitting a first unmodulated carrier signal at a first frequency and a second oscillator for transmitting a second unmodulated carrier signal at a second frequency. The first and second frequencies define the traffic information. The receiver includes a detector for detecting the first and second signals and an announcing device for announcing the traffic information.