forward/redirect taxonomy archive of term to a page with same name

Personally I would not recommend breaking the taxonomy archives – what if someone wants to browse all posts tagged “ferrari”?

You’re better off using the page URL in the first place:

if ( $tags = get_the_terms( $post, 'vehicle' ) ) {
    foreach ( $tags as $tag ) {
        if ( $_page = get_page_by_path( "cars/$tag->slug" ) )
            printf( '<a href="https://wordpress.stackexchange.com/questions/198524/%s">%s</a>', get_permalink( $_page ), get_the_title( $_page ) );
    }
}