HEFEI — A Chinese company has partnered with a research institute to develop fog radar to be used on expressways to improve warning systems.

While fog can be forecast by weather bureaus, there are blind zones in fog where the density is high and visibility is further reduced. The new device will be able to tell how far a vehicle is from such blind zones and warn the driver on the spot.

Its developers - Anhui Zhongkai Information Industry Co Ltd and Hefei Institutes of Physical Science of Chinese Academy of Sciences - said the margin of error is now under 7.5 meters, and they plan to mass produce the radar next year.

Drivers will be notified about fog by electronic warning boards on expressways or through messages sent to their mobile phones.

Heavy fog is a cause of serious road accidents worldwide. In China, more than 2,500 expressway sections each reported at least three occurrences of heavy fog on average last year, according to government figures.

The province of Anhui, where the radar's developers are based, is frequently hit by fog. In a recent accident, 18 people were killed after a massive pile-up of 30 vehicles at a section of expressway shrouded by heavy fog.

China has fog forecast radar, but its use is largely restricted to scientific research because of its high costs.

"The new radar can do a better job and is much cheaper to make," said Zhou Jian, with the Anhui company.

Zhou said the device is in final testing. The first devices will be used in Anhui.