Many accidents that cause bodily harm involve crashing into an obstacle. The stakes are high, given that, in France, for the period 1999-2003, there were 3431 deaths involving an obstacle, in other words, 34% of deaths on the roads in urban areas. Although restricting driving speeds is a key factor in improving accident rates, this is not enough on its own. It is possible to take action to reduce the number and seriousness of accidents involving obstacles in urban areas.In the longer term, the use of breakaway posts is one new measure that may help improve the situation. Extensively used in Scandinavian countries for street lamps, signposts and various other posts, this device serves to limit the seriousness of impact in the event of veering off the road, by collapsing or bending on impact. Use of these posts is currently at the experimental stage in France.