1. Initial Traffic Stop: The first step in the DUI arrest process in Massachusetts is the initial traffic stop. Law enforcement officers can pull over a driver if they have reasonable suspicion that the driver is operating a vehicle under the influence of alcohol or drugs. For example, if a driver is swerving between lanes or driving erratically, it may give the officer reasonable suspicion to initiate a traffic stop.
2. Sobriety Tests: After the traffic stop, the officer may request the driver to perform field sobriety tests (FSTs). These tests are designed to assess the driver's coordination, balance, and mental acuity. Examples of common FSTs include the walk-and-turn test, one-leg stand test, and horizontal gaze nystagmus test. These tests help the officer determine whether there is probable cause to believe the driver is under the influence.
3. Chemical Testing: If the officer has probable cause to believe that the driver is under the influence, they may request the driver to submit to a chemical test. In Massachusetts, the chemical test typically involves a breathalyzer or blood test to measure the driver's blood alcohol concentration (BAC). Refusal to take the chemical test can result in automatic license suspension under Massachusetts' implied consent law.
4. Booking and Release: If the driver is arrested for DUI, they will be taken into custody and transported to the police station for booking. During the booking process, the driver's personal information will be recorded, fingerprints may be taken, and any personal belongings will be collected and stored. After the booking process is complete, the driver may be released on bail or held until their arraignment.
5. Arraignment: The arraignment is the first court appearance after a DUI arrest. At this stage, the driver will be formally charged, and they will enter a plea of guilty, not guilty, or no contest. The court will set a date for the next hearing, which may include pre-trial motions, plea negotiations, or trial.
6. Pre-Trial Motions and Hearings: During this stage, the defense and prosecution may file pre-trial motions to challenge the admissibility of evidence or seek other legal remedies. The court will hold hearings to consider these motions and make rulings that will impact the case.
7. Plea Negotiations or Trial: Depending on the circumstances and strength of the evidence, the case may proceed to trial or be resolved through plea negotiations. If the case goes to trial, both sides will present their arguments and evidence, and the judge or jury will make a determination of guilt or innocence. If a plea agreement is reached, the driver will enter a plea and be sentenced accordingly.
8. Sentencing: If the driver is found guilty or pleads guilty, the court will impose a sentence. Sentences for DUI convictions in Massachusetts can include fines, license suspension, mandatory alcohol education programs, probation, and even jail time, depending on the severity of the offense and any prior convictions.

It's important to note that the DUI arrest process in Massachusetts may vary depending on the specific circumstances of each case and any changes in the state's laws. For the most accurate and up-to-date information, it is always advisable to consult with a qualified attorney or refer to the Massachusetts General Laws.