headlight recommendation for my Duster
WHY they are not DOT approved, I have no clue. They certainly should be.
Because they are different standards developed seperately over many decades.
One obvious reason many US States did not allow them is that the lenses weren't molded with the nibs for the mechanical aimers. Since the mechanical aimers were how these states checked headlights were pointing where they should, the European stuff was off road only as far as they were concerned. This seems to have started to change in the mid 90s. Now one of the last hold holdouts NJ apparently doesn't even check headlight aim at annual inspection (at least that's my impression drving at night the past year).
:soapbox:
I agree it would nice if the US and ECE countries could resolve the differences in approach and testing.
Dan Stern summarizes the differences post 31
Best headlights for 9004 bulbs? '95 Mazda Mx6 - Page 2
Fortunately, in the past few years many states have come to accept e-code lamps as replacements.
U. S. Federal legality of ECE type-approved auxiliary lamps
Updated Hella "Super" 7" H4 Headlights
FWIW the older sealed beams are legal but dont have DOT or SAE molded into the lenses.
Also one that bit me was Hella makes an H4 lamp assembly marked DOT but actually was only for Motorcycle use. The high/low split is really annoying. I gave those away and bought the DOT version back when the Barracuda was still registered and inspected in NJ. Much better.
I'm sure Dan Stern can say much more about the differences and why E codes are not or can not generally be also DOT accepted.