Quote Originally Posted by dbuzz View Post
if its too slow talaga, hazard lights coupled with head lights are ok lalo na kung walang car sa likod mo. this is to give warning to the incoming car/s that there's a hazard. and change lane only when its extremely necessary.
Generally this isn't OK, but I know of one exception.

In Germany, part of "autobahn etiquette" is to turn on the hazard lights when you see gridlock or a very slow crawl up ahead and you're driving at, say, 60 km/h or faster. This is to warn drivers behind you that they have to brake for the traffic jam up ahead as well.

That's part of Car and Driver's recent feature: "Eight Rules for Driving the German Autobahn."
http://www.caranddriver.com/reviews/...tobahn_feature