Using expressway's number of lanes and traffic volume, and volumes on entrance, exit, and service road as input, the methods gives the minimum separation distance based on the given level of service.

该计算方法以快速路主线车道数、主线流量、出入口流量、辅道流量为输入条件，计算满足一定服务水平下的出入口最小间距值。

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The study recommended a minimum vertical separation distance between fracking wells and water supplies of 600m (2, 000ft).

BBC: Fracking: Untangling fact from fiction