+1
"If you don't see correctly, then the other aspects of safety, such as brakes, are less effective as they come on later," says Dominiek Plancke, general manager of automotive, Philips Lighting.
I don't know about anyone else on here, but I think that if someone can't see correctly, they should stop driving and get their eyesight corrected. If the problem is simply low daylight levels, then slow to a speed where you can see in the distance you can see to be clear. All extra lights on a car do (in low daylight or at night in lit streets) is to make that car more visible. Xenon lights are provably less safe for oncoming road users because they are more dazzling; they are less safe for the road users behind the Xenon-lit car for the same reason.
"In Germany, for instance, you could save 18% of the lives lost in traffic if all cars were equipped with Xenon headlights," he says, referring to a study by technical services firm TUV Rheinland.
Compare the arguments used for seatbelts:
http://john-adams.co.uk/wp-content/uploads/2006/SAE seatbelts.pdf