Innovative bootstrap approach for the estimation of minimum measurement time interval in road traffic noise evaluation

It is observed that in order to characterize the environmental noise in a site, during diurnal reference time (6-22 h) or nocturnal reference time (22-6 h), relatively at preset time window, observation period, a single value of the equivalent continuous A-weighted sound pressure level LA,eq is used. This value is determined by integrating and averaging the squared A-weighted sound pressure of fluctuating noise during the measurement time interval, in which there are representative values of acoustic event pressure levels: so it is very important accurately to select the suitable integration time. Such matter are highly relevant to the area of measuring environmental noise and this paper aims to present a statistical method, for determining the minimum measurement time interval for an accurate estimation of LAeq. The proposed algorithm, based on CPER bootstrap method, has been experimentally verified with real data obtained from road traffic noise measurement and it showed a very good stability. The methodology is suitable for upgrading the level meter firmware in order to have the real time information on the measurand uncertainty estimation and on the minimum measurement time interval.