If you don't build a freeway and people still need to get to that place, they will do it via surface arterials or neighborhood streets causing the neighborhoods to become much less safe due to through traffic that should be on a freeway.
Or they'll carpool or take mass transit and let someone else drive. Or they'll ride a bike and pass all that traffic. Or they'll move closer to where they need to be. Or they'll work a different shift when traffic is lower.
You bring up a good argument for eliminating minimum parking requirements that cities force upon developers and business owners. If there were less parking available at your destination, you might try to avoid the busier periods so you can find a parking space (if parking is unpriced) or cheaper parking, or you would find a different way to get there.
I don't know of any case where variable tolls set at market equilibrium have increased traffic congestion on surface streets.