I find it ironic that if you ask a dozen officials of ANY State DOT about something like this,you'll likely get a dozen different,and often contradictory,answers. So far Nevada is the worst I'm aware of for this-even THEY don't know the rules for sure,but they sure "know" when you're VIOLATING the rules.
Speed


1954 GMC 350
1957 GMC 1/2 ton
1962 Chevy C-30
1952 Chevy 6400 dump bed project truck
'98 Harley FLSTC
'66 Pontiac Catalina
'76 Chevy 1 ton Duallie
'84 Bronco II
'78 Dodge W-200
'81 Toyota 4X4 truck