A reasonable snow emergency vehicle scheduling could not be achieved based on personal experience because of the complexity of urban road network.

城市道路网络复杂，合理的除雪车辆调度方案仅仅依靠人工经验无法实现。

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This paper established an integer programming model of the snow emergency vehicle scheduling which considered the realistic constraints such as the fleet size and the level of service.

本文考虑冬季道路养护中的服务水平、车队规模等约束条件，建立了实习信息下除雪车辆优化调度的整数规划模型。

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The storm had dumped over two feet of snow in a few short hours and a state of emergency was declared. The roads were impassable, phone lines were jammed and we all felt helpless.

这是一次突发事件，这场暴风雨在几小时内就下了2尺，道路无法通行，电话也不能接通，我们感觉到很无助。

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Philadelphia declared a snow emergency Tuesday night, while public schools there and in Boston were closed.

CNN: Winter storm pounds New England

Menino said the city's snow emergency and parking ban will be lifted at 9 a.m.

CNN: Winter storm pounds New England

For, as Espen points out, if we didn't treat snow as an emergency, we wouldn't get our snow days.

CNN: Don't treat snow as an emergency