The boards of supervisors of the counties within the district may contribute to the contingent fund from any funds of the several counties not otherwise appropriated, including any moneys received from the State by the counties as a result of any tax or license upon motor vehicles or motor vehicle fuels. The State may contribute to the contingent fund any amount that it may desire out of any funds available for joint highway district purposes. The State may, through the director of public works, designate the purposes for which any money contributed by it to the contingent fund may be used and the purposes designated may be any which are authorized under the provisions of this part.