Road traffic noise levels, restrictions and annoyance in Greater Cairo, Egypt

This study concerns road traffic noise in Greater Cairo, the capital and the largest city in Egypt and the eleventh biggest city in the world. Extensive measurements were carried out in 21 sites in Greater Cairo. Restrictions were introduced to improve environmental conditions including: (i) a ban on horns, (ii) a ban on horns and trucks, (iii) a ban on horns, trucks and noisy buses. Equivalent noise levels (L_Aeq) were measured before and after these restrictions. The equivalent noise level was considerably reduced by the bans. This shows that the town planner can use various strategies to change the traffic composition in order to achieve quieter city environments. The degree of annoyance was measured by means of questionnaire. The results showed that there was a strong relationship between road traffic noise levels and the percentage of highly annoyed respondents.