Any person operating a motor vehicle on Lincoln Park Board of Education property in the City shall operate the same at a careful and prudent speed, not greater than nor less than is reasonable and proper, having due regard to the traffic, the surface and width of the traffic lane in which the vehicle is traveling and any other conditions then existing. In no event shall any such person operate a motor vehicle on such property at a speed greater than that which will permit him or her to bring the vehicle to a stop within an assured clear distance ahead. In no event shall the speed of any vehicle operated on such property exceed fifteen miles per hour. (1979 Code Sec. 10.63.030)