In all municipal corporations of this state having a population of 350,000 or more according to the United States decennial census of 1980 or any future such census, the municipal authorities of such municipal corporations are authorized to close any municipal streets adjacent to or through institutions of higher learning during any hours in which the municipal authorities determine that it is in the best interest of the public safety and welfare to do so. For the purposes of this Code section, "public safety and welfare" shall be defined to include not only considerations of the flow of traffic, but may also include a determination that to close said streets during such hours will enhance police protection on said streets.