Creating a traffic jam is super easy. Just use the domino effect. If you're on the highway and tap your brake just enough that the car behind you also needs to brake, you've created a jam. The car behind the car that braked will brake harder since they noticed later and this will continue until someone does a full stop, completely stopping traffic.
Thus, regardless if you're a good driver or a bad one, you will not see the jams you created or prevented.