With temperatures topping 37 C, authorities in Shanghai have begun watering the city's two elevated roads in a bid to keep them cool.

 

The city has eight watering vehicles, and will continue with the program this year whenever temperatures exceed 35 C. It is the first time the city has watered the elevated roads, Shanghai's major traffic arteries.

 

The vehicles watered 20 kilometers of road in the middle of the day yesterday, using 128 tons of water.

 

"We choose to conduct watering on elevated roads from noon to 2 pm because in this period the traffic flow is usually 30 percent lower than normal," said Peng Jianrong, office director of Shanghai Municipal Maintenance & Management Co, Ltd.

 

He estimated that watering would reduce temperatures on elevated roads by 6 to 7 C for a short period.

 

According to their research, temperatures on bituminous road surfaces will reach 50 C if the air temperature exceeds 35 C.

 

This extreme heat can result in burst tyres, a frequent occurrence in the hot summer, Peng said, without offering statistics.

 

"Such cooling measures will also give the drivers more comfort, though the actual effects might not last long," he added.

 

The city has in the past refrained from watering the elevated roads due to high traffic volumes, but it does water many other roads in the city.

 

But some local drivers were concerned that the slow water vehicles would cause jams on the road.

 

"Smooth traffic condition is far more important than temperature of the road surface and the possible cooling comfort," said a local driver named Zhou Ming.

 

(China Daily August 1, 2006)