Local authorities in their respective jurisdictions shall place and maintain such traffic devices upon public highways under their jurisdiction as are necessary to carry out the provisions of the law or local traffic ordinances or to regulate, warn, or guide traffic. Cities and towns, which as used in this section mean cities and towns having a population of over fifteen thousand according to the latest federal census, shall adequately equip with traffic devices, streets that are designated as forming a part of the route of a primary or secondary state highway and streets which constitute connecting roads and secondary state highways to such cities and towns. The traffic devices, signs, signals, and markers shall comply with the uniform state standard for the manufacture, display, direction, and location thereof as designated by the department. The design, location, erection, and operation of traffic devices and traffic control signals upon such city or town streets constituting either the route of a primary or secondary state highway to the city or town or connecting streets to the primary or secondary state highways through the city or town shall be under the direction of the department, and if the city or town fails to comply with any such directions, the department shall provide for the design, location, erection, or operation thereof, and any cost incurred therefor shall be charged to and paid from any funds in the motor vehicle fund of the state that have accrued or may accrue to the credit of the city or town, and the state treasurer shall issue warrants therefor upon vouchers submitted and approved by the department.