cars now have sound!!!

managed to sort out the car sound problem, before the cars would pass by the screen with no sound , but now i have them hit a mark and the sound plays , took me a while but i figured it out, i created two sounds in adobe soundbooth , on of a normal car passing by and other with the radio on playing a beatles song. which works really well. there not on a random timer but the uneven times that the cars reapear give the impression of random.