Fast Company | Suzanne Labarre | Ingenious Flipper Bridge Melds Left-Side Drivers With Right-Side DriversAnswer: this proposed bridge.
Hong Kong drives on the left side of the road, mainland China on the right. So how do you prevent crashes when driving between them?
This is so simple and so genius I'm shocked one of these doesn't exist somewhere else yet.
(Via Mrs. SB7, who thinks there's a Wee Britain joke to be made in here somewhere, but neither of us can think of one.)