I noticed that when there's heavy rain, silver cars are practically invisible in rear view mirrors unless their lights are on. Particularly when there's plenty

I noticed that when there's heavy rain, silver cars are practically invisible in rear view mirrors unless their lights are on. Particularly when there's plenty of water on the rear windshield. I think in my developing country daytime running lights have been made mandatory for all new vehicles, but the millions of existing vehicles don't have them, and their drivers don't bother to turn them on during rains.