Re: It's OK
Tim, please correct me if I am obviously wrong:
The largest cost of a road is the initial construction, operation is relatively low and not much dependant on the use. That means that as society has put down the money for the damned thing (sunk cost), it better use it as much as possible.
This means that, as long as the capacity of the road is rarely used, tolls are against good economics.
You have a prime example very close to home: The A22 (Algarve east-west motorway) is with tolls, and the N125 (~A-road) which runs parallel is free. The result is a clogged up, accident-prone N125 and a grossly underused A22.