Traffic Drum Issues

Though I have not come across many people who have had a problem or an issue with their traffic drum, I am sure they exist.  One issue I know about is the shape of the bottom of the drum.  Supposedly it is a federal spec that they have to be made in such a way that if they fall over, they do not roll.

One of the solutions is to make a drum that is an oval shape at the bottom.  Another way of solving this is by making a drum with lips or ridges at the bottom to stop it from rolling.