Section 21: Arrest without warrant
Section 21. Any officer authorized to make arrests may arrest without a warrant and keep in custody for not more than twenty-four hours, unless a Saturday, Sunday or a legal holiday intervenes, any person who, while operating a motor vehicle on any way, as defined in section one, violates the provisions of the first paragraph of section ten of chapter ninety. Any arrest made pursuant to this paragraph shall be deemed an arrest for the criminal offense or offenses involved and not for any civil motor vehicle infraction arising out of the same incident.
Any officer authorized to make arrests, provided such officer is in uniform or conspicuously displaying his badge of office, may arrest without a warrant and keep in custody for not more than twenty-four hours, unless Saturday, Sunday or legal holiday intervenes, any person, regardless of whether or not such person has in his possession a license to operate motor vehicles issued by the registrar, if such person upon any way or in any place to which the public has the right of access, or upon any way or in any place to which members of the public have access as invitees, operates a motor vehicle after his license or right to operate motor vehicles in this state has been suspended or revoked by the registrar, or whoever upon any way or place to which the public has the right of access, or upon any way or in any place to which members of the public have access as invitees, or who the officer has probable cause to believe has operated or is operating a motor vehicle while under the influence of intoxicating liquor, marihuana or narcotic drugs, or depressant or stimulant substances, all as defined in section one of chapter ninety-four C, or while under the influence from smelling or inhaling the fumes of any substance having the property of releasing toxic vapors as defined in section 18 of chapter 270, carbon tetrachloride, acetone, ethylene, dichloride, toluene, chloroform, xylene or any combination thereof, or whoever uses a motor vehicle without authority knowing that such use is unauthorized, or any person who, while operating or in charge of a motor vehicle, violates the provisions of section twenty-five of chapter ninety, or whoever operates a motor vehicle upon any way or in any place to which members of the public have a right of access as invitees or licensees and without stopping and making known his name, residence and the register number of his motor vehicle goes away after knowingly colliding with or otherwise causing injury to any person, or whoever operates a motor vehicle recklessly or negligently so that the lives or safety of the public might be endangered in violation of paragraph (a) of subdivision (2) of section 24 and by such operation causes another person serious bodily injury as defined in section 24L, or whoever commits motor vehicle homicide in violation of subsection (a) or (b) of section 24G.
Any person who is arrested pursuant to this section shall, at or before the expiration of the time period prescribed, be brought before the appropriate district court and proceeded against according to the law in criminal or juvenile cases, as the case may be, provided, however, that any violation otherwise cognizable as a civil infraction shall retain its character as, and be treated as, a civil infraction notwithstanding that the violator is arrested pursuant to this section for a criminal offense in conjunction with said civil infraction.
An investigator or examiner appointed under section twenty-nine may arrest without a warrant, keep in custody for a like period, bring before a magistrate and proceed against in like manner, any person operating a motor vehicle while under the influence of intoxicating liquor or marihuana, narcotic drugs, depressants or stimulant substances, all as defined in section one of chapter ninety-four C, irrespective of his possession of a license to operate motor vehicles issued by the registrar.