The reason for the constant sounds are probably because the ‘Event Hit’ keeps getting triggered. What is your solution for when there is a crash? Is the vehicle pushed back, can it continue forward, is it set to bounce back but then continue forward again?
This is more of a logic issue and can be solved multiple ways. One simple way is when there is a hit event triggered, make a variable that will stop it triggering again until after a delay. This isn’t the best but should stop the machine gun noise. The other methods involve making sure that the crash isn’t possible to fire every frame that the vehicle keeps colliding, which may mean pushing apart the two objects when they collide.