China's New Longest Underwater Tunnel Has An LED Ceiling

The LED displays are meant to prevent driver fatigue in the 6.65-mile tunnel

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Photo: ChinaFeature

How long are you willing to drive underground? How about long enough that you could have a lull in concentration behind the wheel? Well, a video light display might be enough to keep drivers engaged until they make it to the light at the end of the tunnel. This week, the new longest underwater tunnel in China opened to traffic after four years of construction with this interesting feature.

The Taihu Tunnel traverses for 6.65 miles under Lake Taihu. The tunnel and freshwater lake are located roughly 30 miles west of Shanghai. The Taihu Tunnel is a segment of a newly-built highway connecting Shanghai, China’s most populous city, and Nanjing, a former national capital. While dwarfed by Norway’s nearly 9-mile long Ryfast undersea tunnel, 6 miles is reasonably long for a highway tunnel. For comparison, the tunnel built to replace the Alaskan Way Viaduct in Seattle, Washington is 1.75 miles long and is one of the longest in the United States.

It reportedly took over 70 million cubic feet of concrete to construct the Taihu Tunnel. There are three ventilation complexes across the lake’s surface to circulate fresh air throughout the six-lane tunnel. The project’s sheer scale and $1.5 billion price tag are impressive, but one feature immediately caught my attention.


Chinese highway authorities installed LED lights on the tunnel ceiling to combat driver fatigue over what would have been a dull, monotonous drive underground. The displays seem to be visually engaging by displaying images and not a blanket wall of color. Basically, it is a high-tech version of the trivia roadsign seen on some of Australia’s desolate highways. I’ll have to remember to check in on the Taihu Tunnel in a decade to see if the LEDs aren’t a flickering horror show or entirely out of use.