An aerial view of the "sound insulating tunnel"

Construction of a "sound insulating tunnel" on an elevated freeway near the Beijing Zoo was completed on Sunday. The tunnel will prevent animals in the zoo from being disturbed by traffic noise emanating from the nearby freeway.

The dome of the sound-proof wall stretches for nearly one kilometer. This section of the freeway is the first road of its kind in Beijing. The dome design uses closed sound insulating material so that people and animals located outside the tunnel can't hear the sound generated by moving vehicles inside.

The 1.8 km elevated freeway is expected to alleviate traffic pressure in Xizhimen, a major hub of communications in the northwest city environs. This stretch of the road is expected to open to traffic by the year's end.

Open-air habitats accommodating monkeys and bears in the zoo have been relocated to make room for the freeway.

(China.org.cn November 12, 2007)