A one-parameter model (ξ) for stop-and-go noise is developed. The physics of the phenomenon is based on the idea of the linear density of radiated energy. The methodology of ξ determination has been worked out and illustrated. The noise interaction with the surface of the ground is considered to be the only wave phenomenon that disturbs geometrical spreading. The model makes possible the calculation of the correction term in the time-average sound level, LAT, as an adjustment to the constant speed model of traffic noise.