Even the geographically inept are probably aware that not every country drives on the right side of the road, as we do in North America. For some, that moment of clarity may come when watching James Bond eject some henchman from his Aston Martin; for others, it may happen during a tragic car accident on Downton Abbey. I saw my first right-hand-drive car as a kid, when my friends’ parents started driving the non-export model of a Japanese minivan for some reason. But from that time on, one question always kept me up nights: What happens on the highway when a drives-on-the-left country meets a drive-on-the-right country? I couldn’t see any alternative but one vast, unending, Blues Brothers-style traffic accident in both directions. Let’s head to the former Portuguese province of Macau to see my favorite solution to the problem.

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There are surprisingly few land borders on Earth where right-hand-drive countries meet left-hand-drive ones. Thanks largely to the British Empire, a majority of the world used to drive their cars and carriages on the left—including the U.S. until the early 19th century, and parts of Canada into the early 20th. But many countries—most of Eastern Europe, parts of Scandinavia, Korea, Argentina, the Philippines—have joined the drive-on-the-right bandwagon during the past hundred years. In fact, most of the remaining major drive-on-the-left countries (Britain, Japan, Australia) are islands, so the border problem doesn’t really come up. Other major exceptions (southeast Africa, the nations that were once British India) come in clusters that mostly border each other.

There are a few nations that do have to worry about how to switch traffic at the border. Left-driving Thailand is one; three of its neighbors, Cambodia, Laos, and Myanmar, drive on the right. Most of its high-traffic borders just use a traffic light to alternate the flow of vehicles—a simple solution, when you think about it.

But there are more elegant arrangements, ones that allow for continuous traffic—such as the bridges of Macau. Macau was a Portuguese colony for more than 400 years, and at the time it was handed back to China in 1999, it was the last European colony in Asia. Like Hong Kong, Macau still drives on the left under Chinese rule, which means travelers between Macau and other parts of China must switch sides of the road without even leaving the country! At the Lotus Bridge between Macau and Hengqin Island, cars on the Chinese side loop under the bridge on a weirdly asymmetric partial cloverleaf in order to switch lanes.