Methods for predicting noise in the vicinity of signalized intersections

Abstract

To accurately estimate the noise at a signalized intersection, it is necessary to precisely reproduce the traffic volume, signal cycle and traffic noise for each vehicle behavior and driving state. Precise reproduction requires considerable effort, such as continuous calculations of vehicles and the setting of parameters such as engine speed, engine load and velocity. A simple method that involves using A-weighted sound power levels (L WA) under nonsteady running conditions has already been proposed for estimating noise at signalized intersections in a previous paper. In this study, the authors developed two simple methods for predicting noise in which the effects of acceleration and deceleration by signals is reflected. One method is based on a microsimulation traffic model, in which equivalent continuous A-weighted sound pressure levels (L Aeq) is calculated by adding the noise of vehicles passing a green signal and the noise of vehicles decelerating and stopping at a red signal then accelerating when the signal turns green. The other method is even simpler and involves the assumption that an intersection zone is an unsteady running section and that L WA for a nonsteady running section is larger than that for a steady running section. Noise predicting by the three simple methods is compared with actual measurements at 10 sites. The two new methods had slightly improved accuracy relative to the measured results.

Road traffic noise prediction model ``ASJ RTN-Model 2013'': Report of the Research Committee on Road Traffic Noise

“…A method of calculating L Aeq separately for vehicles that pass a green signal under a steady condition and for vehicles that decelerate, stop and accelerate when the signal is red under a transient running condition [46].…”

“…A simple method of calculating L Aeq by setting L WA separately for a steady-state flow section and a compound section with steadystate and accelerating flow sections [46].…”

“…Therefore, if one studies the effect of the signal phase on the noise level in detail, it may be important to consider the running behaviors of individual vehicles in the noise calculation. In this case, one can apply the semi-precise method (practicable method) [46], which calculates the noise in the vicinity of the signalized intersection from the unit pattern of individual vehicles, or one can apply a simple method [46] that is a simplification of the semi-precise method. The outline of these calculation methods are described in Appendix A3.…”

“…In this appendix, other calculation methods such as a practicable method (semi-precise method) and its simplified method are described (see Table A3.1). [46] For each signal cycle, noise is separately calculated for vehicles passing a green signal and for vehicles decelerating, stopping and accelerating at a red signal for each lane. In the calculation, the mean A-weighted sound power level L WA [dB] is applied as the power level of running vehicles, which is determined by taking account of the component ratios of different vehicle types.…”

Road traffic noise prediction model "ASJ RTN-Model 2008": Report of the Research Committee on Road Traffic Noise

“…In this appendix, a semi-precise method and its simplified method are described. [74] For each signal cycle, noise is separately calculated for vehicles passing a green signal and for vehicles decelerating, stopping and accelerating at a red signal for each lane. In the calculation, the mean A-weighted sound power level " L L WA [dB] is applied as the power level of running vehicles, which is determined by taking account of the component ratios of different vehicle types.…”