How to make a minecart dismount its passenger?

I want to loop through all minecarts and for each one, dismount its passenger.
Is this at all feasible? I know how to loop through all regular mobs and dismount them if they happen to be on a minecart (as detected by a predicate). But then I'm checking far more individual entities, few of which will ever actually be in a Minecart, instead of only checking every minecart (which there will be far fewer of).