Passengers are queueing up to get across the world's longest sea bridge but it's the bus drivers who are being especially careful. And not because the bridge requires them to switch from driving on the right (China) to the left (Hong Kong).
Fortunately there's a merge point (where cars stop and safely cross from one side to the other) called the Pearl River Necklace for that.
No, the issue for transport personnel is to make sure they get enough sleep and not eat too much salt for dinner.
Why?
Drivers crossing the bridge are fitted with blood pressure monitors and are being scanned by facial recognition cameras which detect if they yawn more than three times in 20 seconds.
What happens if they do?
An alert is sent to authorities where a possible fine will be incurred. You yawn, you pay Yuan.
The 55km bridge took nine years to build, (the same as Sydney Harbour Bridge), and cost $20billion (Sydney cost $13.5million). It includes a 6.7km section that dips under the water so the ocean traffic above can continue business as usual.
But it's not technically open to the general public. You have to make a donation of 5 millions Yuan (approx $720,000), or have government connections to use it.
Suffice to say this is a bridge that encourages the use of public transport where safety is a key issue, which is possibly why the yawn-cams have been installed.