Except as provided in subsection (b) of this section, a public local law enacted by the county commissioners of a code county takes effect: 45 days after it is enacted; or at a later date specified in the public local law. A public local law takes effect on the date of its passage if it is passed as an emergency bill. An emergency bill may not: abolish or create an office; change a salary, term, or duty of an officer; grant a franchise or special privilege; or create a vested right or interest.