mm.. the player car is the car demo codes, whereas the ai car is quite long and messy and linked everywhere. =\ not sure how to paste the whole chunk.

increasing the wait time does helps, but the checkpoint only detects the player occasionally, and sometimes perform time_left +=20; sometimes add_laps_player();
cranky!!

function checkpoint1_event(){
proc_kill(4);// so that there is only one instance of this function running

if (you==player)
{
add_laps_player();
time_left += 20;
my.flags |= PASSABLE;
wait(50);
my.flags &= ~PASSABLE;
}
else {
my.flags |= PASSABLE;
wait(5);
my.flags &= ~PASSABLE;
}

}

What other methods is good for detecting a checkpoint? i tried scan but it scans too many times..