Beijing's Changping district traffic police join hand with the capital's firefighters and first-aid personnel to conduct a tunnel emergency drill along G7 highway on Thursday. [Photo/CFP]

Highway tunnels' special features add to the difficulties of practicing the emergency plans. A drill where a bus catches fire after crashing into a Hazchem truck in a tunnel means the teams not only have to carry out a successful rescue mission, but also have to ensure that there is minimal affect on the traffic. It also requires perfect coordination between different departments so as to prepare for real accidents.

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