A friendly nod or a wave of acknowledgement in response to an act of courtesy helps to create an atmosphere of goodwill and tolerance so necessary in modern traffic conditions.

对礼貌行为的友好点头或挥手感谢有助于创造带有善意的宽容氛围，这在现代交通条件下是非常必要的。

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He waited for a policeman to stop the traffic and wave the people on.

他等着一位警察来让车辆停下，挥手让众人前行。

《柯林斯英汉双解大词典》

An ultimate goal in traffic regulation is "the green wave," the bam, bam, bam of greens that allows platoons of vehicles to move smoothly through intersection after intersection.

交通管制的终极目标是“绿色波浪”，也就是那些能让车辆队伍流畅的穿过一个接一个的交叉路口的，啵，啵，啵作响的一路绿灯。

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But they are frequently at the mercy of traffic managers, the civilians in brightly colored vests who wave motorists through intersections during Midtown's jammed midweek afternoons.

WSJ: Decoding Traffic In a Jammed City

Money will come from the second wave of government Pinch Point funding designed to solve local traffic problems.

BBC: Great Yarmouth to have new ?4.7m road to ease bottleneck

Passenger traffic is rare on the CPR these days, so rare that farmers and even trackmaintenance workers wave and cheer like the Railway Children as we pass.

BBC: The wonders of Canada by rail