traffic beam

Noun

 * 1)  A headlight setting intended for roads with traffic on them at night.
 * 2) * 1940, Ralph A. Richardson, Optics and Wheels, General Motors Corporation, p. 25
 * For your own safety and that of others, follow the suggestion in the verse:
 * “Use country beam
 * When roads are clear,
 * Use traffic beam
 * When cars are near.”