In 2001, 273 cities conducted noise monitoring on the road traffic, with 59 ones over the previous year.

2001年，273个城市进行了道路交通噪声监测，比上年增加了59个城市。

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Through field monitoring, the variation laws of road traffic flow, vehicle speed and vehicle type are analyzed, as well as the relationship between road noise and traffic condition.

通过实地监测，分析了某干道车流量、车速、车型的变化规律及其与道路噪声的相互关系，并对选择的交通噪声预测模型进行了精度检验。

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Current municipal traffic monitoring systems study individual stretches of road that use induction loops to sense the passage of cars, or complex camera systems that capture licence plates.

BBC: Tech that trumps traffic tangles