Strictly speaking, a compensatory tax is based on the nature. and the extent of the use made of the roads, as, for example, a miJeoage or ton-mileage charge or the like, and if the proceeds are devoted tp the C repair, upkeep, maintenance and depreciation of relevant roads and the collection of the exaction involves no substanti'al interference with the movement. The expression 'reasonable compensation' is con".enient but vague. The s1andard of reasonableness can only lie in the severity with which it bears on traffic and such evidence of extravagance in its assessment as come from general considerations. What is essential for the purpose of securing freedom of movement by road I). is that no pecuniary burden should be placed upon it which goes beyond a proper recompense to the state for the actual use made of the physical facilities provided in the shape of a road. The difficulties are very great in defining this conception. But the conception appears to be· based on a real distinction between remuneration for the provision of a specific physical service of which particular use is made and a burden placed upon transportation in aid of the general expenditure E of the state. It ts clear tlr.at the motor vehicles require, for their safe, efficient and economical use, roads of considerable width, hardness and durability; the maintenance of such roads will cost the government money. But, because the users of vehicles generally, and of public motor vehicles in particular, stand in a specral and direct relation to such roads, and may be said to derive a special and direct benefit from them, i.t seems not unreasonable that they should be called upon to · F make a special contribution to their maintenance over and above their general contribution as taxpayers of the State. If, however, a charge is imposed, not for the purpose of obtaining a proper contribu1tion to the maintenance and upkeep of the road, but for the purpose of adversely affecting trade or commerce, then it would be a restriction on the freedom of trade, commerce or iµtercourse ( 1).
