The highways and transportation commission shall have authority to plan, locate, relocate, establish, acquire, construct, maintain, control, and as provided by law to operate, develop and fund public transportation facilities as part of any state transportation system or program such as but not limited to aviation, mass transportation, transportation of elderly and handicapped, railroads, ports, waterborne commerce and intermodal connections, provided that funds other than those designated or dedicated for highway purposes in or deposited in the state road fund or the state road bond fund pursuant to sections 30(a) or 30(b) of this constitution are made available for such purposes. No moneys which are distributed to the state transportation fund pursuant to section 30(b) shall be used for any purpose other than for transportation purposes as provided in this section.