Vanishing point is about perspective, and the singular pleasure and pain of being human.
What motivates the start of the movie is not that he ‘bets‘ his friend he can do the trip – Kowalski demands a car: he has, for a motive never stated, to leave that night and return to SF.
There is a lot un-said in this movie. It does not have the answers. Just a looming question: Why? And a simple answer, provided by Cleavon Little’s Super Soul: the last free spirit in America – speed is freedom, and, with it taken (forgive the pun) America, and, Kowalski, dies.
There are lot of details: girls, corrupt cops, simple people, simple evils… but for me, what hung it all in place was speed… skiing down a mountain, driving a car, piloting a space ship… liberation is fundamentally connected to MAD (mass * acceleration * distance). And if people thought this movie was mad, they missed the joke: it’s on you, friend.
post script: this review gives a lot of valuable detail about the film, including an explanation of why it is so visually stunning: The cinemtographer was A. Alonzo who created the aesthetic that is so important for Roman Polanski’s wonderful Jack Nicholson FIlm noir classic, Chinatown (1974).