not GVW but size - any vehicle 80" or wider requires clearance lights at each corner and 3 identification lights 6-12" apart top/center, as well as front and rear side markers if over 30' long .... since enacted as Federal Motor Vehicle Safety Standard 108, they've been OE [simplified chart here] .... originally the front clearance lights were green, and that's "grandfathered" in [pre-59 vehicles in Canada]

some folks think it's cool to put them on pickups, but that can be misleading in nighttime emergencies when they're ID purpose may be critical

Bill


Moved over to the Passing Lane

"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir
"When we tug a single thing on an old truck, we find it falls off" ~ me
Some TF series details & TF heater pics