if the roads are sufficient then you don't have congestion.
That's correct, and when the price of using them is set at the market equilibrium price, the roads will be sufficient in that supply and demand will be in equilibrium. Setting the price below the market equilibrium rate is never a good long-term strategy.
The optimal amount of road lane-miles is not the amount where there's never any congestion when the price is zero, but the amount where the cost of traffic congestion equals the price of the tolls or the cost of adding more road.
Variable pricing does not fix capacity, it rewards incompetence.
And that's why restaurant managers who set different lunch and dinner prices do so because they are incompetent.
No, incompetence is setting the price below the market equilibrium rate as a long-term strategy.