I proposed a variation on this idea several years ago, but no one would listen to me. I thought of it one day while watching the Daytona 500.
Sponsor a contest with a million dollar prize for five years. Different engineering teams can enter the race with any street legal production car. The main requirement would be they must modify the car’s propulsion system so that it does not run on gasoline. It can run on water, solar, electric, hydrogen, or some combination. The winner of the 500 lap race wins the million dollars. Anyone can enter the race but the primary entrants would be engineering teams from various colleges and universities: Cal Tech, MIT, FL inst. of Technology, Georgia Tech, Univ. of Maryland, etc.
At the end of the race the winning technology is shared with all the teams. To win in subsequent years, the team must better the time and technology of last year’s winner. In five years or less we would have cars and SUVs that do not run on gasoline.
College kids and graduate students are a better audience for this type of contest because they are not handicapped by assumptions about what can and can’t be done; they are more creative and energetic.