Recently, Plus reported on work done by mathematicians from the Universities of Exeter, Bristol and Budapest into why traffic jams often occur for seemingly no reason.

Now, for the first time, researchers from several Japanese universities have recreated this effect by placing 22 vehicles on a 230-metre single-lane circuit. The drivers drove at a steady 30 kilometres per hour, and whilst initially the traffic flowed smoothly, eventually a backwards travelling shock-wave developed which forced some cars to almost stop and others to increase their speed to 40 kilometres per hour to catch the car in front.

Watch the video below, which comes from the New Scientist channel on you-tube. You can read more about this in the original New Scientist article.