Traffic laws are generally uniform in all countries we visited; if you’re used to driving in the US or Canada, be sure to look up details, as there are some differences. Turning right on a red light is never allowed, and overtaking another car on the right is generally forbidden. There are complex precedence rules; unless specifically signed, the car coming from your right has precedence if all else is equal. Expect people to know and respect these rules; especially German drivers have a habit of not even looking to the left when crossing an intersection. Things are a little more relaxed in Eastern Europe, though, except for drinking and driving, where there’s absolutely zero tolerance for alcohol.

Unless otherwise indicated and depending on the country, speed limits are 50 Km/hour in urban areas, 90 or 100 Km/hour on secondary (single-lane) highways, and 120 or 130 Km/hour on divided (multi-lane) highways. The German Autobahn is an exception; there’s a minimum speed of 60 Km/hour, a recommend speed of 130 Km/hour, and no speed limit at all in the leftmost lane. Avoid that lane unless you have a high-powered car and practice driving at high speed; as I had neither, I usually puttered along at a glacial 120 Km/hour.

In contrast, Brazilian highways have a speed limit of 80 Km/hour for single-lane and 110 Km/hour for multi-lane; one is usually advised to drive slower because of the frequent pot-holes. In Europe I didn’t see a single pothole outside of the quite frequent and very well signed road work areas.

Keep an eye on what other drivers do in regard to speed limits. In most areas everybody drove at or at most 10 Km/hour over the limit. Pedestrians are usually respected, except for Hungary, where they drive more like they do in Brazil – meaning, don’t expect a driver to stop just because you stepped on the road. German and Austrian drivers are the most mild-mannered ones, except on the Autobahn, where most suddenly turn into raving maniacs.

Generally there are no multi-language highway and traffic signs, so it pays to look up and memorize some common words like “exit”, “attention” and so forth in the various languages. Here’s a good site further detailing the various signs and traffic laws. Here’s another one. Signs vary considerably from American conventions in some respects, most rental car companies will give you a chart if you ask for one.