China's mega bridge to monitor drivers' yawns & blood pressure
HONG KONG: The world's longest sea bridge was officially inaugurated on Tuesday by China's President Xi Jinping with supporters hailing it as an engineering triumph and detractors calling it a controversial white elephant.
Here are some facts about the remarkable new multi-billion dollar structure that connects the two semi-autonomous cities of Hong Kong and Macau to the sprawling Pearl River delta economic zone via the Chinese mainland city of Zhuhai.
In terms of sheer size, it is a record breaker -- the longest ocean bridge and tunnel system in the world.
The total length runs a whopping 55 kilometres (34 miles), far further than any other rival bridge and tunnel combination.
Chinese state media said 420,000 tonnes of steel were used in its construction -- enough for 60 Eiffel Towers -- alongside 1.08 million cubic metres of concrete.
It is built to last at least 120 years and can withstand typhoon winds of up to 340 kilometres an hour.
The bridge's unusual undulating structure is designed to keep open vital navigation channels in the Pearl River Delta, which boasts some of the world's busiest ports.
On its western flank the bridge leaves Zhuhai and connects with Macau before heading for 29.6 kilometres across the delta.
Three cable stayed bridges raise the road high enough for large ships to pass underneath.
But then the road plunges below the sea, entering a 6.7 kilometre long tunnel -- which the biggest container vessels can navigate over -- before rising back above the waves and continuing onto Hong Kong.
Until now residents of Zhuhai, Macau and Hong Kong have used ferries to zip between the three cities -- something detractors said illustrated why the costly bridge was unnecessary.
But engineers say the structure will significantly cut down travel time, from four hours between Hong Kong and Zhuhai to just 45 minutes.
This is not a bridge anyone can just drive on -- only the wealthy or politically connected will be able to take their private cars across.
