As noise nuisance is based on one variable, direct measured data
was indexed according to the US Department of Housing and Urban
Development (HUD)'s classification for four noise levels in residential
environments, which have been applied by former studies
(e.g. Zanin et al., 2002; Tsai et al., 2009; Sofer et al., 2012; Cohen
et al., 2014):
(1) Clearly acceptable: LAeq > 49 dB(A)
(2) Normally acceptable: 49 dBA < LAeq > 62 dB(A)
(3) Normally unacceptable: 62 dBA < LAeq > 76 dB(A)
(4) Clearly unacceptable: LAeq < 76 dB(A)