SPEED FREQUENCY-DISTRIBUTION IN AIR-POLLUTANTS EMISSIONS ESTIMATE FROM ROAD TRAFFIC

The work discusses the aspects linked to the speed in the application of the CORINAIR methodology to urban areas. In particular, the introdu ction of a speed frequency distribution (in thirteen classes with rang e 10 km/h) by vehicle category is discussed. A study on sensitivity fi nalized to the analysis of the influence of speed on the emissions is presented. Many cases are examined in which, keeping the average speed constant, a different speed distribution is introduced. The estimates obtained through the simulations are compared with those obtained usi ng a single average speed. The result is that a deeper knowledge of dr iving characteristics and speeds is essential to understand means of t he estimates for those pollutants whose emission dependence on speed i s strongly non-linear.