It does not seem necessary that the expense of those public works should be defrayed from that public revenue, as it is commonly called, of which the collection and application are in most countries assigned to the executive power. The greater part of such public works may easily be so managed, as to afford a particular revenue sufficient for defraying their own expense, without bringing any burden upon the general revenue of the society.
A highway, a bridge, a navigable canal, for example, may in most cases be both made and maintained by a small toll upon the carriages which make use of them: a harbour, by a moderate port-duty upon the tunnage of the shipping which load or unload in it.
… When the carriages which pass over a highway or a bridge, and the lighters which sail upon a navigable canal, pay toll in proportion to their weight or their tunnage, they pay for the maintenance of those public works exactly in proportion to the wear and tear which they occasion of them. It seems scarce possible to invent a more equitable way of maintaining such works.
… When high roads, bridges, canals, &c. are in this manner made and supported by the commerce which is carried on by means of them, they can be made only where that commerce requires them, and consequently where it is proper to make them. Their expense too, their grandeur and magnificence, must be suited to what that commerce can afford to pay. They must be made consequently as it is proper to make them. A magnificent high road cannot be made through a desert country where there is little or no commerce, or merely because it happens to lead to the country villa of the intendant of the province, or to that of some great lord to whom the intendant finds it convenient to make his court. A great bridge cannot be thrown over a river at a place where nobody passes, or merely to embellish the view from the windows of a neighbouring palace: things which sometimes happen, in countries where works of this kind are carried on by any other revenue than that which they themselves are capable of affording.
Even those public works which are of such a nature that they cannot afford any revenue for maintaining themselves, but of which the conveniency is nearly confined to some particular place or district, are always better maintained by a local or provincial revenue, under the management of a local and provincial administration, than by the general revenue of the state, of which the executive power must always have the management. Were the streets of London to be lighted and paved at the expence of the treasury, is there any probability that they would be so well lighted and paved as they are at present, or even at so small an expence?
… The abuses which sometimes creep into the local and provincial administration of a local and provincial revenue, how enormous soever they may appear, are in reality, however, almost always very trifling, in comparison of those which commonly take place in the administration and expenditure of the revenue of a great empire. They are, besides, much more easily corrected.