Subject to all other speed restrictions of this chapter no person shall drive a vehicle not designed for carrying passengers and equipped with pneumatic tires at a speed in excess of:
(1) Twenty miles per hour in any business district;
(2) Twenty-five miles per hour in any residence district;
(3) Forty miles per hour on open country highway;
(4) Trucks licensed at eight thousand pounds gross vehicle weight or less shall be permitted the same speed as passenger cars.