It's possible to change the incentives.

If the roads are free they fill up until gridlock makes them more painful than the alternatives. If you charge money then the expense becomes part of the cost/benefit calculation. It favors car pooling, rich people (who don't care about the price) and other people who urgently need to get somewhere during rush hour (who can pay the price that one time).

You can also just do car pool lanes, which has some similar benefits.