I guess leaderboard is defined by "Cars that have sustained the rigors of NTSB-style testing to determine roadworthiness and are available for sale to the mass

I guess leaderboard is defined by "Cars that have sustained the rigors of NTSB-style testing to determine roadworthiness and are available for sale to the mass public." Cars are nowhere near efficient, they are just in a nice point between practicality and efficiency for their given use-cases.