The buses crashed through a metal railing and hung precariously over Interstate 5 for several hours before tow trucks pulled them back on the road.

A BLUE metal fence runs through Zango, a commuter town along the main road out of Luanda, Angola's capital.

There is a large "stop" sign at the entrance to the road, backed up by a metal barrier and a hand-written poster in red paint proclaiming: "No Trespassing."