Ahh, a long rainy day. As a driving instructor, I'm spending the entire day in traffic, working with my students on proper techniques for inclement weather.
Over the last four hours, I've seen dozens of drivers breaking the law. Which law, you may ask? The one that requires drivers to turn their headlights on whenever they use their windshield wipers. Full headlights, not just parking lights or daytime running lights (neither of which lights improves your visibility to drivers behind you).
The point of the law isn't to help you see better - it's to help you be seen better by other drivers. And it's been the law in our state since January, 2007. That's almost six years now, and still people are driving about in the rain without their headlights on. It makes my driving instructor brain hurt.
If you're out and about on this dreary day, remember the law and use your headlights with your wipers. It'll make you easier to spot to other traffic, and that keeps you safer.