If people aren’t free to adjust their driving habits, congestion pricing merely raises the cost for them, because the time to commute doesn’t go down (appreciably) — everyone is still on the road at the same time.
It then effectively becomes a regressive tax: those least free to change their schedule are those in the lowest earning jobs, and hence those most coerced to pay the cost.
I’m not sure I believe that’s an effective way to raise money for government.