抄録
This study concerns road traffic noise in Greater Cairo, the capital of Egypt, the largest city and the biggest 11th city in the world. Measurements taken in September and October 2001 for road traffic noise levels in Greater Cairo, indicates that noise levels in the city are higher than those set by Egyptian noise standards and policy to protect public health and welfare in residential areas, equivalent continuous A-weighted sound pressure level (LAeq)=80 dB and higher are recorded, while maximum permissible level is 65 dB. LAeq are measured, and tabulated for 23 locations spread over urban zones of city. It has been found out that 91.3% out of locations display during day their LAeq are over 65 dB, and 73.8% out of total number of locations their LAeq are over 70 dB. Results of curbs (restrictions) to improve environmental conditions found that, in absence of horns, LAeq decrease at all sites, maximum reductions range between 9.4 dB and 10.8 dB occurred in downtown area. Omitting buses give a further reduction in LAeq varying between 2.6 to 3.7 dB. In absence of horns, trucks and buses, reductions in LAeq range between 6.0 to 10.2 dB. This shows that the town planner can use various strategies to change the traffic composition in order to achieve quieter city environments.
