Alternative Mobility Funding Systems; Authorizing certain local governments to adopt an alternative mobility planning and fee system or, in certain circumstances, an alternative system; specifying requirements for the application of an adopted alternative system; revising requirements for the calculation of impact fees by certain local governments and special districts; requiring certain mobility fees to be updated within a specified timeframe; specifying criteria to be used by a local government in calculating a mobility plan and mobility fee for transportation mitigation improvements; providing that mobility fee credits must comply with the Florida Impact Fee Act in any mode that creates equivalent capacity that is designated in a local government capital improvements list, etc.