Interrupted Flow Noise Emission Levels for Vehicles in Thailand

Abstract

The development of basic noise emission levels for vehicles in Thailand in the condition of interruptedtraffic flow is presented in this paper. The basic noise emission levels are classified into 8 classes in accordancewith the following vehicle types: passenger car, light truck, medium truck, heavy truck, tractor trailer, bus,motorcycle, and Tuk-tuk. The maximum A-weighted sound levels (LAFmx ) of accelerating vehicles and correspondingspeeds were collected from several individual pass-by vehicles in Bangkok and other provinces. Four sound levelmeters were situated at the distances of 15, 30, 60 and 120 meters from the imaginary stop line with 15 meterssetback from the centerline of the nearest travel lane for the measurement of maximum sound levels at the frontsof all instruments. The vehicular instantaneous speeds at the same locations with LAFmx measurement were alsomeasured. The LAFmx of eight types of vehicles were then plotted against the corresponding speeds to determinetheir relationship. The results indicate that the eight vehicle types are significantly different in their acousticalfeatures. Furthermore, the resulting basic noise emission levels are significantly different from those in theFHWA Traffic Noise Model (FHWA TNM) due to the country-to-country differences in vehicle characteristics.

Keywords : Interrupted Flow / Basic Noise Emission Level / Traffic Noise / Intersection