I drove to Iowa over Christmas. The state was just finishing up clearing the roads from a fairly major snow storm. As I drove down I-35 I noticed a ton of cars in the ditch, which was kind of odd I thought. Turns out that the state of Iowa imposes a tow ban during a major snow storm.
I'm not sure what to think of this, seems like overkill, but the more I thought about it the better I liked the idea. It keeps tow trucks from getting on the road and causing accident, directly or indirectly. It also might keep people off the roads who know that if they do go in the ditch they can't get their car out. Sounds like a great plan considering the amount of traffic you find on the roads in Minneapolis during any given snowstorm.