The picture is a sign for an unmanned level crossing.

图中是无人看守铁路道口标志。

The dog is walking down the street, when he comes to a level crossing.

狗狗沿着街道走到了一个十字路口。

When one red light at a level crossing is on, the vehicles may pass if it is safe to do so.

道路与铁路平面交叉道口有一个红灯亮时，车辆在确保安全的情况下可以通行。

And a intelligent level crossing signal and video monitoring system were introduced in details.

较详细地介绍了一种智能化道口信号及图像监录系统。

Level crossing accidents menace people's lives and properties and country's transportation lifeline.

道口事故的频发，直接威胁到人民的生命财产安全和国家的经济运输命脉。