[Ducman69]

If everyone has their headlights off during the day, the person with their headlights on sticks out.

If everyone has their headlights on during the day, the person with their headlights off sticks out.

Its common sense.

If DRLs are law, then all you see are a sea of headlights. It does not improve conspicuity. The human brain very quickly just tunes it out. Many motorcycles install headlight modulators on their bikes which makes the headlights flash, and it really does make you stick out.... but if you had a sea of cars with flashing headlights, it would blend in with the background and wouldn't help at all. Legislators rarely use common sense though.