Many of the countries have ways to try to get you to slow down. Trying to convey this without using words to avoid a language barrier presents its own problems.
In Britain and Ireland there were signs in each of the cities that say how many deaths there were on the highway in the last year. In the more rural areas they showed statistics for the whole county and stretched it out for the last 4 years. The problem with this is that since I am from Los Angeles where there are so many people these numbers seem so low. It makes me think that the roads are safe and I speed up. In Los Angeles people dying on the freeways is communicated as time being added to your commute so I have become somewhat cynical.
In France they had life size cut outs of people. Abstract men like on the front of the bathroom door. For some reason some of them had a red stripe on their head like blood dripping down, some more then others. So I can only guess the really bloody accidents get more blood on their heads. The problem with these was when you rounded a corner that it seemed like they had escaped from their bathroom signs and were now trying to take over the world like zombies or something. Seeing these guys standing on the side of the road would likely cause more accidents at that point.
In Romania they hoisted the bashed cars up and put them on a metal post in the ground. The bashed up cars looked more like trophies as you drove by. It was like you too can achieve this if you drive just a little faster. As the sun went down it hid the post underneath so it looked like floating cars over the corn fields.
I think that Hungary had the best idea. The had huge billboards with a claymation guy. With his seatbelt on he was happy. Without it he was splattered on the windshield like Gumby.