The tremendous amount of money necessary to construct present types of roads must, in the long run, be obtained from the citizens through some medium of taxation. A tax is a compulsory contribution levied upon persons, property, business, occupations, privileges, or enjoyment of the people for the support of government or governmental functions. When levied upon persons it is usually called a poll or head tax; when upon property, a property tax; when upon business it may be a capital tax, sales tax or an income tax; when upon occupations, an occupation tax; when upon privileges, a license; and when upon enjoyment, a pleasure tax. A good many of them may be lumped together under the name of revenue taxes. Some are collected personally by a specified officer of the government, while others are collected indirectly by the sale of stamps which are attached to the article or transaction taxed. Taxes may also be classified as direct, indirect and special, all of which are of great importance to the highway. =Direct Taxes.=--Direct taxes are levied directly upon property or persons. State laws usually prescribe that general property taxes shall be levied uniformly over the assessed values of the district concerned. A poll tax is levied on all persons of a particular age or class, as all able-bodied males between the ages of twenty-one and fifty years. An income tax is levied according to some prescribed rule on the annual incomes of persons and corporations. An income tax is really a tax on business, either present or past. In either case, whether the levy is on his poll, upon the assessed valuation of his property, or upon his declared income, the taxpayer contributes, theoretically at least, in direct proportion to his ability to pay. The amount of the tax is definitely ascertained some little time in advance of payment and is collected directly by an officer of government. The levying of labor or poll taxes on persons living within a particular road district easily expanded to the levying of property taxes to care for the local roads. However, as the cost of road building and maintenance increased the fronting or contiguous property could not stand the entire burden, the zone of taxation was widened to include larger areas, the township, the county or the state, depending on the importance of the highway.