So in this specific format it's not about trying to pass. It's about trying to keep up and stay as close as possible. If the leading driver is able to gap the chase driver it's a point. They rotate lead/Chase repeatedly to find out the better performer.
Passing someone on these runs is the sports ball equivalent of a successful Hail Mary to win a game.
They usually have two similarly matched cars (power or weight wise.) with equal skilled drivers to determine the better set-up/machine.
Check out "Best Motoring" "Hot Version" they were Japanese magazines / video magazines where they did a ton of these battles. Incredible stuff.