OK, I've mentioned automatic lights, but you're the only other person who has mentioned them. What is your definition?

Simple (and probably different than your definition ), as in Volvos made for domestic market: DRL turn on when you turn the engine on.

OK, that's fine with me, as long as they aren't as bright as what I've seen. And Bruno, I must strongly disagree that it is a good idea to make DRLs use high beams at any intensity. That's just insane to me.

Regular low beams or a bit stronger 'position' corner lights seem better, I agree.

I still think it would not be good to make them mandatory.

Again, if you cannot count on incomming traffic being made more visible by using the lights, you loose half the purpose. I had several, well, not exactly close calls, but unpleasant surprises when starting to overtake a car in front of me after letting ten incomming ones pass (all with their lights on), only to have eleventh one, grey, dirty and without lights emerge suddenly from haze and backdrop of tarmac.

Why it it would be bad idea to make the lights mandatory? What could possibly be gained by not using them when most of other drivers do?