Additional suggestions that i think would make the game better/harder because the answer distribution is currently pretty skewed and many of your options are just clearly not covered by the rule (though all respect to rule sticklers, general contrarians, and everythings-a-vehicle hipsters):
construction equipment for park improvements (backhoe, etc)
gas powered moped
electric moped
gas powered rc car
4-wheeler/atv/dune buggy
golf cart
segway/monowheel
antique cars for some kind of demo/event
shriner guys in those mini cars in a local parade (at least i think most americans know what i'm talking about)
anti-drunk driving display (they have these sometimes at colleges, and maybe high schools, but it's basically a wrecked car and there are police there to do pr)
Note: i think many of your options are just clearly not covered by the rule, maybe keep some of them but not so many?
construction equipment for park improvements (backhoe, etc)
gas powered moped
electric moped
gas powered rc car
4-wheeler/atv/dune buggy
golf cart
segway/monowheel
antique cars for some kind of demo/event
shriner guys in those mini cars in a local parade (at least i think most americans know what i'm talking about)
anti-drunk driving display (they have these sometimes at colleges, and maybe high schools, but it's basically a wrecked car and there are police there to do pr)
Note: i think many of your options are just clearly not covered by the rule, maybe keep some of them but not so many?