Accounting for non-zero asymptotic annoyance prevalence rates in community tolerance level analyses

Dosage-response relationships between transportation noise exposure and the prevalence of noise-induced annoyance typically assume an asymptotic rate of annoyance of zero at low noise exposure levels. If the annoyance prevalence rate of any sigmoidal function at low exposure levels is non-zero, however, its predictions may not closely match field observations in low exposure ranges. Community tolerance level (CTL) analysis yields a dosage-response relationship that is easily modified to account for non-zero asymptotic annoyance prevalence rates. This presentation describes empirical analyses undertaken to investigate the effects on CTL values of field observations of annoyance at low levels of noise exposure.