THE INFLUENCE OF THE TRAFFIC LIGHT CYCLE ON THE TRAFFIC NOISE AT STREET INTERSECTIONS OF URBAN AREAS

Intersections of urban streets are particularly noisy locations due to the addition of the noise from vehicles at different streets, long periods of noise emission from queuing vehicles with traffic lights in red and the noise from accelerating vehicles. Besides, the traffic lights impose a modulation in the passage of the vehicles, so that the subsequent noise variability along time contributes to increase the annoyance degree. This paper presents an investigation on the effect of the traffic light regulation parameters on the spatial and temporal distribution of the sound pressure levels induced by the vehicle traffic in a street intersection, by means of a simulation code specially developed. The algorithm combines a dynamic traffic model, a model for sound propagation and a model for vehicle noise emission, according to the Harmo-noise guidelines. After an experimental contrast to verify the predictions, the software developed was applied systematically to calculate the L-eq and L-10 distributions corresponding to a real street junction when systematically varying the traffic light settings. Results are presented for a number of reference positions at the intersection area that quantify the effects of the traffic light cycle period and the green-red fraction.