I’m sorry. I couldn’t find a good way to phrase the topic (or put into the search).
Some countries drive on the right side of the road. Others drive on the wrong (er, left!) side. I imagine that somewhere in this vast world that two countries with opposite setups meet…what happens on the roads at the border? Chaos? A swirling vortex of death? Lots of signs with big text?
I’m not sure if any two countries that share a land border have differing sides of road* on which they drive. The cars on the trains in the channel tunnel (England<->France) line up single file, so coming out the other end on the right side of the road is no problem.
[sub]*Not saying there isn’t. Just that with so few countries where people drive on the left- there might not be[/sub]
Sweden used to drive on the left (until late 1966 I think it was). At that time there was no customs/passport requirements to travel between Sweden, Denmark, and Norway. Now you can’t drive from Denmark to Sweden (well not directly) but you could cross the long Swedish-Norwegian border at many places. Where I crossed the border was marked by two signs posted in the middle of the road about ten feet apart. As you crossed from Sweden to Norway they read “Kept left” then “Keep right”. Actually thinking back on it since I couldn’t read either language I assume they were marked with the international symbols for “keep left” and “keep right”. That’s it no trouble at all – of course, the traffic was very light there.
Unca Cecil included a letter from a reader about driving near the Norwegian-Swedish border in this [url=http://www.straightdope.com/classics/a4_242.html]classic SD column. Although it’s true that at the time traffic was light and accidents owing to the change in driving laws were few, increasing car traffic from Norway and Finland was surely one of the reasons Sweden decided to switch. Particularly along the long border between Norway and Sweden, there are many border crossings, few of them guarded in any significant way, and many poorly marked. Even major road crossings are open and most people just drive straight on through. Switching sides at the busy Svinesund crossing would be quite a headache!
You should keep in mind that in most cases of countries which abut each other in this fashion, there are enough other differences that we’re talking about a sealed border which requires stopping for passport control. So there’s no traffic slamming into each other if for no other reason than the fact that people come to a complete stop for that purpose.
The last crossing I did of this sort was on the Thai-Cambodian border. For the most part vehicles will take you to the border, then you get out and arrange the next leg of your travel on the other side. You’re changing languages, cultures, currency and the side of the road you drive on (with corresponding switching of the side of the vehicle the wheel is on in most cases), and most transport workers have no interest in taking you into the neighboring country.
The crossing itself happens in between the two passport control points, is largely by foot for most travellers (freight on trucks gets checked off to the side and re-enters traffic in a roundabout way.) You can hire guys with pullcarts to take your stuff the 50 ft between countries if you have that much to move. You do in fact cross over each others’ paths in a large extended “X” that must look like the simplified diagram of DNA strands you see in a biology text from the air. This is slightly chaotic but not much worse than changing classes in high school.