Relative influence of maximum sound pressure level and tonality of truck tire noise on annoyance for local residents

• A laboratory experiment was carried out to evaluate the annoyance of trucks traffic noise on local residents living near an expressway. • The stimuli were simulations of external tire noise, varying in maximum A-weighted level and tonality. • The results showed that both parameters had an equal effect on annoyance. • Tire noise regulations should be modified to take account of tonality. Tires are becoming the main source of noise from road vehicles, especially for electric vehicles. Especially in the case of heavy goods vehicles, tones can be heard in this tire noise. This study aimed to evaluate the relative influence of tonality and sound pressure level on the annoyance of local residents, in the case of silent engine vehicles (e.g. electric vehicles). Forty-eight people were subjected to four sound conditions varying according to a two-factor experimental design (tonality and maximum sound pressure level) and representing the traffic noise of an urban motorway. Results showed that the presence of an audible tonal component leads to an increase in annoyance equivalent to that of a 12 dB(A) increase in level, well beyond the penalties usually applied. There was also a smaller effect on the fatigue felt by the participants. These results argue in favour of amending tire exterior noise regulations (which only control the maximum sound pressure level), to take account of possible audible tones.