QUOTE(mikef7 @ Jun 25 2008, 03:38 PM)

UNIT A – FOUR-WHEEL MOTOR VEHICLES
LIGHTS
Headlights (one each side, high and low beams)
Turn signals (front and rear)
Taillight (at least one, if equipped with two both
must work)
License plate light
Brake lights.
INTERIOR
Horn
Bright light indicator
Windshield wipers
Windshield washers
Brakes (adequate to stop and hold the vehicle)
Parking brake
Safety belts (1965 and newer models).
WINDSHIELD AND MIRRORS
Safety Glass (no plexiglas, sufficient size to protect
driver and passengers, no cracks, no obstructions,
non-transparent material prohibited)
Outside rearview mirror on driver’s side (adjustable)
Half-ton or more capacity trucks outside rearview
mirrors on both sides.
EXTERIOR
Bumpers (required on passenger vehicles, 14 to 22
inches above the ground except 4-wheel drive)
Tires (2/32 inch tread, no exposed cord or tread
separation, approved for highway use by D.O.T.)
Exhaust (good working order, no excessive noise.
Must include a tailpipe and resonator where the
original design included a tailpipe and resonator)
Differential gear.
So since a quad is a four wheel vehicle it would have to adhere to the regulations above. All the lighting and electrical stuff doesn't seem bad at all, not much to that. Already meets the headlights, brights, bright indicator and break light - tail light requirements. Brakes and parking brake are already taken care of, mirrors would not be a problem. The stock exhaust shouldn't be an issue sound wise.
Looks like the snags would be:
1. Differential gear -- seems like the biggest hurdle to jump
2. Windshield -- wonder how they would interpret that?
3. Bumbers -- again, probably depend on how they interpret it.