From my childhood recollection, there were at least 3 KITT's for "on location" shoots - one for the interior, one for the driving shots, and one that got crashed/shot at/otherwise messed up.

I know this because when I was 9 or so I was riding my bike and saw the Knight Van up on Twin Peaks by my house in SF. I almost shat my pants. We all went up to watch them shoot, and afterwards got a picture with David Hasselhoff, a really nice guy.

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