Why were over half of the vehicles on the road in California from the bay to the central valley have their daylight headlights on?

Why were over half of the vehicles on the road in California from the bay to the central valley have their daylight headlights on?
Most vechicles built after a certain date by law are required to have daytime running lights and it's a good thing ...if you ever see a car comming toward you in the evening with no lights on and the car behind has it's running lights on the difference is well....night and day and it might just save someons life.

most all motorcycles from way back in the 1980's have daytime running lights on , this was way befor car manufactures started doing it.

chet2010