Suggested

Safety car

I think it could be interesting to introduce sometimes a safety car in some races at random. 
This could add suspense to the races :) 

SC could be a consequence of crash, but crashes should not be random, but a consequence. Let's say you overpush an unexperienced driver in any street circuit and as consequence, he crash. He crashed on unsafe place and others could crash in him and as consequence SC is deployed. 

Let's see whether a number system could cope with that though... count in how high the chances are that a driver will crash and it may lead to them not finishing one race in five... so whilst I do still like the idea, it's kinda not random enough to pull through (even if it does make sense)

Some sc element could be interesting but I agree any crashes shouldn’t be random. Maybe with breakdowns with a tired car, over used tyres, or over heated tyres could make a crash more likely...and also the possibility of your car being taken out in a ‘no fault’ crash could be interesting...😉

Thanks for your answers!! I would say we can introduce the SC  when someone have overused  tyres or no more fuel  or other things like that, it could be interesting! :)