Authorities in south China's Guangdong Province have closed part of a trunk expressway following a road collapse caused by subsidence.

Motorists reported the collapse at about midday on Thursday. No injuries or vehicle damage were reported.

One of the piers, coded H32, that supported a bridge along the expressway linking Guangzhou with Shenzhen close to Hong Kong subsided by about half a meter, causing about 50 meters of the road surface to drop, said Lan Hengshui, deputy managing director of the expressway company.

The subsidence left a V-shaped indentation on the Wangniudun section of the expressway, between Guangzhou and the manufacturing town of Dongguan.

One driver, surnamed Chen, said he clearly felt his empty tanker truck go down a ramp and then up again when he passed Wangniudun at 12:15 p.m.. "I pulled into the emergency lane and called the police."

Traffic police immediately closed the Dongguan-Guangzhou section of the expressway, and diverted vehicles to the Beijing-Zhuhai expressway and state highway 107 connecting Beijing and Shenzhen.

The expressway company said the pier was undergoing maintenance when the subsidence occurred.

One witness, a woman surnamed Liu, said she and her husband, a repair worker, had been living for four months in a shed next to the pier. "I was cooking when I heard a crack from the pier. It was so loud that I thought the bridge would fall apart."

The incident raised memories of June last year, when the 1,600-meter-long Jiujiang bridge over the Xijiang River in Foshan collapsed, killing nine people.

The road collapse and subsequent traffic control measures have extended the trip from Dongguan to Guangzhou's Baiyun Airport from 70 minutes to two hours, said Zhong Jinhui, a civil aviation official in Dongguan.

Meanwhile, cargo transport costs from Shenzhen to Guangzhou were likely to rise by at least 20 percent, said Chen Shaopeng, a senior executive from a Guangzhou-based logistics firm.

The provincial transportation bureau said repairs on the road surface will start after the post-Spring Festival traffic peak ends on March 2.

The Guangzhou-Shenzhen Expressway, which opened in 1995, reported a daily average flow of 348,000 vehicles last August, despite its designed capacity of 80,000 vehicles a day.

The operators complained overloaded trucks carrying up to 192 tons, almost four times the country's upper limit of 55 tons, often used the route, but traffic authorities never enforced the regulations.

(Xinhua News Agency February 15, 2008)