policy designed to ensure that all of its workplaces are free from the illegal use, possession, or distribution of controlled substances (as defined in the Controlled Substances Act ( 21 U.S.C. 802 )) by the officers and employees of such department, agency, or instrumentality. 702. Unless otherwise specifically provided, the maximum amount allowable during the current fiscal year in accordance with subsection 1343(c) of title 31, United States Code, for the purchase of any passenger motor vehicle (exclusive of buses, ambulances, law enforcement vehicles, protective vehicles, and undercover surveillance vehicles), is hereby fixed at $19,947 except station wagons for which the maximum shall be $19,997: Provided , That these limits may be exceeded by not to exceed $7,250 for police-type vehicles: Provided further , That the limits set forth in this section may not be exceeded by more than 5 percent for electric or hybrid vehicles purchased for demonstration under the provisions of the Electric and Hybrid Vehicle Research, Development, and Demonstration Act of 1976: Provided further , That the limits set forth in this section may be exceeded by the incremental cost of clean alternative fuels vehicles acquired pursuant to Public Law 101–549 over the cost of comparable conventionally fueled vehicles: Provided further , That the limits set forth in this section shall not apply to any vehicle that is a commercial item and which operates on alternative fuel, including but not limited to electric, plug-in hybrid electric, and hydrogen fuel cell vehicles. 703. Appropriations of the executive departments and independent establishments for the current fiscal year available for expenses of travel, or for the expenses of the activity concerned, are hereby made available for quarters allowances and cost-of-living allowances, in accordance with 5 U.S.C. 5922–5924 . 704. Unless otherwise specified in law during the current fiscal year, no part of any appropriation contained in this or any other Act shall be used to pay the