The use of road charging whether imposed in a closed pricing model by government or arising in an open pricing model in the market is likely to increase, under any likely scenario, in various forms and for various reasons.
These charging schemes have proponents and opponents. Predictably, the proponents are usually those who do not pay the charge (even among those who do pay, because it is passed on to them) and the opponents are usually those who do pay (even among those who do not pay, because they recharge it).
The effectiveness and perceived success of these schemes is likely to depend to a large extent on the support for them. Increasing this support involves changes which turn opponents into proponents.
Among the opponents, there are a wide range of arguments based on a number of factors. Many opponents are not opposing payment, they pay a great deal already; but are concerned about the fairness, effectiveness, benefits and viability of these schemes.
One factor is the assumed models of how these schemes do and/or might operate and the likely price incurred; more information and examples can improve understanding of the alternatives in this area.
Another, and for many the overriding, factor is the destination of the funds raised by these schemes. One of the most effective ways in which these concerns might be reduced is to regulate the spending of the funds.
So if the charges paid by road users were ring fenced to be spent on road transport, and particular if this had the effect of changing the choices made by road users and, thereby, reduced congestion, then many opponents might become proponents.
The details of the examples which are relevant to any particular opponent depend on the basis of their objection to road congestion. However, in general, whether the main objection to road congestion is increased journey times or pollution (both in total and locally) or damage to buildings or whatever, if the funds were spent on improved traffic information systems, or on research and education on improved planning and driving behaviour, or on improved and alternative propulsion systems or on techniques for planning the reduction and elimination of journeys, then many people might see the benefit of paying.