Tires don't have collision with eachother?

Hi there,
Firstly i would like to start off by saying i was just goofing around and i wanted to try starting a vehicle with another vehicle via the traction of the tires. Funny stuff, if i put lower gear ratios on one the engine could go boom and so on, as you do in beamng. what took me by surprise is that tires don't have collision with eachother, only with other body parts, is there any particular reason why? Thank you everyone in advance.

 

Tires has nodes with disabled self-collision, so they can't have a collision with other nodes.

 

Almost all vehicles tires have self-collision.
But yes, some ones like the T-Series and the Autobello Autobuggy

 

Somebody make a mod recently that added tire collision to some cars.