We do, in fact, charge people for access to public parks. The parks still serve their purpose.
The price mechanism is what allows for efficient allocation of scarce resources. There's nothing wrong with using it. Demanding that scarce things be free is just imposing a price control, and price controls always lead to shortages and misery.
There may be no fee to access (most of them) per use but you need to pay for a vehicle, jump through some expensive regulatory compliance hoops (insurance, registration, inspection/emissions if applicable in your state) and then pay for consumables (primarily fuel but also tires) and maintenance.
Congestion also imparts a cost though it is not directly monetary (time valuable, all else being equal people will choose the faster option).
If alternate forms of transit (subway, bus) are available people will naturally load balance to them based on their situation.
If you want to reduce road congestion without making people's lives worse then make public transit better and more available. Don't arbitrarily increase the price of the roads. Tolling all the roads to decrease usage is no different than a fuel shortage that drives up prices (something we can all agree is not good for anyone). Too many people depend on private cars for increasing cost to be a good strategy.
I guess I hate to be a person who does not agree, and thinks higher prices is actually good for mostly everyone. Higher prices means less driving! Which means reductions in auto accidents, noise, pollution, obesity, and sprawl. Add leads to more fuel efficient vehicles and transit options.
I would like bus/rail fares to be as low as possible. Ideally all transportation would be Free(TM) and getting where you want to go would cost nothing more than the time to get there. Obviously being Free(TM) is a pipe dream but something as simple as getting from A to B should at least be cheap and effective enough that it is not something that requires significant expense or planning.
The ability to go places is essential for society to function in the same way that drinking water and getting rid of trash are. It is something every member of society needs access to. With the current state of public transit networks increasing the cost of road usage is about as useful to society as taxing private wells in areas without municipal water.
Cars as a technology have their downsides but they are an integral part of our society at present and for the foreseeable future. Doing things to restrict them or increase cost to decrease over use and abuse would have net negative consequences for society. We should emphasize rail and bus for new transit development in urban areas but we shouldn't handicap the existing capacity for cars.
This idea that some good should be free leads only to misery, since nothing is actually free, and to provide a good for free ultimately just means taking it by force from someone to give to someone else, usually in a manner motivated by sentiment. That's not a recipe for efficient allocation of scarce resources.
I clarified my original point. I'm very much not in favor of price controls. I'm even less in favor of the government artificially jacking the price of things though as a sin tax (which is essentially what adding tolls to reduce usage is). The government should use carrots (more better alternatives) not sticks (increased cost).
Roadway space may be somewhat scarce in some areas now but transit infrastructure is not a finite resource. We can always build more. In urban areas we should probably build something other than roads (i.e. subways) though.
The price mechanism is what allows for efficient allocation of scarce resources. There's nothing wrong with using it. Demanding that scarce things be free is just imposing a price control, and price controls always lead to shortages and misery.