Hmm, is there a link?

As the days get shorter and everything gets darker sooner due to all the clouds I've noticed that there are more idiot drivers around (for example, more than once recently I've reached the top of hills where the central markings are dashed and solid in my favour to find cars on my side of the road because they've decided to overtake cyclists just then). I wonder if there's something linking poor weather and idiot drivers.