Recent studies on urban noise pollution have demonstrated that in metropolitan areas, prolonged exposure to traffic noise exceeding 70 decibels significantly correlates with an increased incidence of stress-related cardiovascular conditions. However, the installation of acoustic barriers along major highways only reduces noise levels by an average of 5 decibels. Furthermore, in districts where speed limits were reduced from 50 mph to 30 mph, average traffic noise dropped by over 12 decibels. Curiously, the districts that implemented both acoustic barriers and speed limit reductions experienced no greater decrease in average traffic noise than those that only reduced speed limits.
Which one of the following is most strongly supported by the information above?
- ADecreasing traffic speeds from 50 mph to 30 mph is the most effective way for a metropolitan district to reduce the incidence of stress-related cardiovascular conditions.
- BIf a metropolitan district has an increased incidence of stress-related cardiovascular conditions, its average traffic noise must exceed 70 decibels.
- The noise reduction effects of acoustic barriers and speed limit reductions are not entirely cumulative when both are implemented in a district.Cevap
- DMetropolitan districts that maintain traffic noise levels at or below 70 decibels will not experience an increased incidence of stress-related cardiovascular conditions.
- EAcoustic barriers are incapable of reducing traffic noise by more than 5 decibels under any circumstances.