It turns out there is also a law about turning on your car's headlights when using the windshield wipers. Every time it rains I hear the weather man remind us drivers to "turn on those headlights," and I finally looked it up (online of course). There it is, right there in the California Driver Handbook:
Use Your Headlights
- When it is cloudy, raining, snowing, or foggy. If weather conditions require you to use your windshield wipers, you must turn on your headlights.
This is a good thing because I have a hard time seeing dark cars driving on the freeway in pelting rain--when the water is not just pouring down from the sky, but is also shooting up at you, spewing from the tires of the car in front.