Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 90C, § 4

Nothing in this chapter shall prevent a person other than a police officer from applying for a criminal complaint for an offense that constitutes a criminal automobile law violation under subsection (B) of section three of this chapter, and such person need not show that the violator has been issued a citation in connection with such violation.

Nothing in this chapter shall be construed to prevent a police officer from arresting any person without a warrant pursuant to the provisions of section twenty-one of chapter ninety for such criminal offenses and in such circumstances as are specified in said section. If any such arrest is made, it shall be noted on the citation and all copies of the citation except the police officer's copy and the police department copy shall be forwarded to the clerk-magistrate of the appropriate district court and one copy of same shall serve as the application for complaint. If an arrest is made and the citation is issued electronically, such notation of arrest shall be made on the printed copy and on any additional printed copies provided to the court and shall be made on the electronic record of the citation as agreed upon by the administrative justice of the district court and the registrar. The police chief may from time to time designate one person to sign all such complaints. If such arrest is made in good faith, the arresting officer shall not be liable in civil proceedings arising from such arrest.

Any provision of this chapter to the contrary notwithstanding, any payment of a penalty, fine or assessment made pursuant to the provisions of this chapter, including the payment of an assessment for a civil motor vehicle infraction, shall operate as a conviction for purposes of registry of motor vehicles action pursuant to chapter ninety and for purposes of the safe driver insurance plan established pursuant to section one hundred and thirteen B of chapter one hundred and seventy-five.

Nothing in this chapter shall be construed to prevent access by probation officers to driving records of offenders maintained by the registrar or by the motor vehicle insurance merit rating board.