(a) On-street parking means parking a motor vehicle on any street, highway, or roadway, except for legal stops within designated loading zones or areas defined for loading purposes, at or before intersections, as caution, safety and emergencies require, whether or not a person remains in the vehicle.

(b) Commencing on or before June 30, 1974, the Commonwealth, the City of Boston, the City of Cambridge, and administrative bodies of any of them having jurisdiction over any streets, highways, or roadways within the City of Cambridge or Boston proper, and the principal officials and administrative bodies thereof having responsibility over parking on such streets, highways, or roadways, shall adopt all necessary administrative and enforcement procedures and regulations to effect a prohibition of on-street parking within Boston proper between the hours of 7 a.m. and 9:30 a.m., and within the City of Cambridge between the hours of 7 a.m. and 10 a.m., except Saturdays, Sundays and legal holidays. The regulations shall state that violation of the prohibition shall be punishable by a fine of not less than $15. The City of Boston shall at a minimum eliminate 50 percent of on-street parking during the hours specified by January 1, 1976; 662⁄3 percent by September 1, 1976; and 100 percent by March 1, 1977. The City of Cambridge shall at a minimum eliminate 331⁄3 percent of on-street parking during the hours specified by September 30, 1974; 662⁄3 percent by July 1, 1975; and 100 percent by March 1, 1977. Any other affected entity shall at a minimum eliminate 331⁄3 percent of such parking during the hours of 7 a.m. to 10 a.m. by January 1, 1976; 662⁄3 percent by September 1, 1976, and 100 percent by March 1, 1977.

(c) The following classes of vehicles shall be exempt from the requirements of this section, provided that on-street parking by such vehicles is in compliance with local and state regulations:

(d) On or before June 30, 1974, no owner or operator of a motor vehicle shall park, or permit the on-street parking of, said vehicle within Cambridge or Boston proper except in conformity with the provisions of this section and the measures implementing it.

(e) The Governor and the chief executive of any other governmental entity on which obligations are imposed by paragraph (b) of this section should, on or before April 15, 1974, submit to the Regional Administrator for his approval a detailed statement of the legal and administrative steps selected to effect the prohibition provided for in paragraphs (b) and (d) of this section, and a schedule of implementation consistent with the requirements of this section. Such schedule shall include as a minimum the following:

(f) Upon a finding that substantial hardship would otherwise be experienced by employees of employment facilities located in Cambridge, the Director of Traffic and Parking of the City of Cambridge may issue special parking stickers to such employees which shall entitle vehicles to park during the hours of the ban. Such stickers shall be valid only for those streets and areas of streets clearly identified on the face of such stickers, shall be issued with preference being given to carpools and vanpools and shall be subject to immediate revocation if the vehicle is cited for a parking violation on a street or area other than those designated. A list of all persons receiving such stickers shall be sent to the Regional Administrator on or before July 1 of each year.

(g) The ban shall not apply to any street space which is subject to metered parking with a maximum allowable time limit of one hour.