OUI / DUI Drunk Driving Defense Lawyer in Greater Boston

A person arrested for drunk driving in Massachusetts is charged with operating under the influence of intoxicating liquor, commonly called OUI, under G.L. c. 90, § 24. After the arrest, the police apply for a criminal complaint in the District Court or the Boston Municipal Court. The person then faces the criminal case in court and a possible suspension of their driver’s license by the Registry of Motor Vehicles.

The police officer takes the operator’s driver’s license and suspends it on behalf of the Registry of Motor Vehicles if the operator refuses a breath test, or if the breath test final analysis is .08 or greater. The arrest by itself does not suspend the license. A person later convicted of OUI, or whose case is continued without a finding, also loses the license for a period set by statute.

This page explains what the Commonwealth must prove, how defense counsel challenges breath tests and field sobriety tests, and the license and other consequences of a conviction or a refusal. Attorney Serpa has tried OUI cases in the Greater Boston courts since 1995.

G.L. c. 90, § 24(1)(a)(1) criminalizes operating a motor vehicle on a way or in a place where the public has access while under the influence of intoxicating liquor or drugs. In an alcohol case, the Commonwealth may prove the offense in either of two ways: impaired operation, or operation with a blood alcohol percentage of .08 or greater. The first way is the impairment theory.

The second way is the per se theory. Under the per se theory, the Commonwealth must prove the qualifying test result instead of impaired driving. A judge following Massachusetts District Court Criminal Model Jury Instruction 5.310, “Operating Under the Influence of Intoxicating Liquor” (rev. Mar. 2023), instructs the jury that impairment and the per se theory are two ways of committing one offense.

The Elements the Commonwealth Must Prove

The Commonwealth must prove three elements beyond a reasonable doubt. The elements are operation, a public way, and either impairment or a blood alcohol level of .08 or greater. The defense may challenge the evidence on each element.

Operation is defined broadly. Under the governing definition, a person operates when, while in the vehicle, the person intentionally performs an act or uses a mechanical or electrical component that, alone or in sequence, will set the vehicle’s motive power in motion. Commonwealth v. Uski, 263 Mass. 22, 24 (1928); Commonwealth v. Wurtzberger, 496 Mass. 203, 206 (2025). The vehicle need not move, and the engine need not be running.

In Wurtzberger, the evidence showed that the defendant was in the driver’s seat with the ignition key turned far enough to power the radio while the engine remained off. The Supreme Judicial Court held that the evidence permitted a finding of operation because turning the key was an intentional act in the sequence that could set the vehicle’s motive power in motion. A person’s private intent merely to use the vehicle as a stationary place does not prevent a finding of operation.

The defense often contests operation when the police find a driver parked, stopped on the shoulder, or asleep behind the wheel. The defense then examines whether the evidence shows an intentional act to engage the vehicle and whether another person may have driven.

The public way element concerns the place where the operation occurred. In the words of the statute, the operation must occur upon a way or in a place to which the public has a right of access, or to which members of the public have access as invitees or licensees. G.L. c. 90, § 24(1)(a)(1). The word “way” is defined in G.L. c. 90, § 1.

G.L. c. 90, § 24 limits the public-access element to a place that the public may reach by motor vehicle. The public-access element depends on the status of the place, not on the status of the driver. Commonwealth v. George, 406 Mass. 635 (1990). Courts evaluate objective indicia of public access, including paving, curbing, street lights, traffic signals, and abutting homes or businesses. Commonwealth v. Smithson, 41 Mass. App. Ct. 545 (1996).

The decision whether a place is one of public access is a legal conclusion that an appellate court reviews on the objective circumstances. Commonwealth v. Virgilio, 79 Mass. App. Ct. 570 (2011). A parcel posted against trespassers and used without the owner’s permission is not a place of public access. Commonwealth v. Callahan, 405 Mass. 200 (1989). A private lot behind a locked gate is ordinarily not a place of public access. The Commonwealth must prove the public-access element with evidence about the place.

The Commonwealth proves the third element in one of two ways. On the impairment theory, the Commonwealth relies on observational evidence that the person’s consumption of alcohol impaired the ability to operate a motor vehicle safely. Commonwealth v. Connolly, 394 Mass. 169 (1985). The Commonwealth does not have to prove erratic driving, only a diminished capacity to drive safely.

On the per se theory, the Commonwealth relies on a blood alcohol level at or above .08 percent, shown by the breath test final analysis from a certified breath test or by a hospital record. The Commonwealth does not have to prove impairment at all on the per se theory. Commonwealth v. Colturi, 448 Mass. 809 (2007). The .08 percent criminal threshold applies regardless of age. For a person under 21, the separate administrative license provisions of G.L. c. 90, § 24(1)(f)(2), and § 24P apply to a result of .02 or greater.

The Breath Test

The breath test used in Massachusetts is the Draeger Alcotest 9510. For the breath test final analysis to be admissible, a certified breath test operator must administer the test on an infrared breath-testing device certified under the governing regulations, using approved methods. Breath test operator certification is valid for three years under 501 CMR 2.07(3). The device certification is valid for one year under 501 CMR 2.06. G.L. c. 90, § 24K.

The regulations require an adequate breath sample, a control-standard analysis, and a second adequate breath sample, in that order. The Office of Alcohol Testing certifies the devices and sets the standards under 501 CMR 2.00. Each device must be certified. A device certification is valid for one year. The control-standard result in a valid test must read between 0.074 and 0.086.

A missing annual certification, a bad calibration record, or a departure from the required testing sequence is a problem with the foundation of the breath test final analysis. A judge can exclude the breath test final analysis because of a problem with its foundation. The firm explains the instrument and the science in detail on its pages on the breath test and the Alcotest 9510 and on defending the breath test.

In the consolidated Ananias litigation, the District Court established a historical presumption of exclusion for the breath test final analysis from an Alcotest 9510 machine last calibrated and certified before April 18, 2019. The court established the presumption after the Office of Alcohol Testing withheld failed calibration worksheets. Limited case-specific exceptions applied to motor vehicle homicide, OUI serious bodily injury, and fifth-or-subsequent-offense prosecutions.

The breath test final analysis from an Alcotest 9510 machine calibrated and certified on or after April 18, 2019, is admissible again, subject to a case-by-case challenge to the reliability of the particular machine. In an individual case, admissibility still depends on the Commonwealth’s producing the certification and calibration records applicable to the machine when the test was administered.

The Breath Test Refusal

A driver may refuse the breathalyzer. A refusal causes an immediate Registry suspension that is separate from any suspension imposed through a court disposition. Under G.L. c. 90, § 24(1)(f)(1), the refusal suspension is 180 days for a driver age 21 or older with no qualifying prior offense.

The refusal suspension is three years for a driver under 21 or a driver with one qualifying prior offense, five years with two qualifying prior offenses, and lifetime with three or more qualifying prior offenses. Three prior offenses means the current arrest would be treated as a potential fourth offense. For the refusal suspension, a qualifying prior offense can include an OUI conviction, an admission to sufficient facts followed by a continuance without a finding, or assignment to a qualifying alcohol or controlled-substance education, treatment, or rehabilitation program. A qualifying out-of-state disposition may also count as a prior offense.

Separate 10-year and lifetime refusal provisions apply after specified prior serious-injury, motor vehicle homicide, or manslaughter convictions. The refusal suspensions are Registry consequences. The refusal suspension period does not depend on a conviction in the new criminal case.

A refusal is not admissible against the driver at trial. The statute provides that evidence of a refusal is not admissible in a civil or criminal proceeding. G.L. c. 90, § 24(1)(e). The exclusion of refusal evidence also has a constitutional basis. A statute that made breath test refusal admissible in a criminal case would violate article 12 of the Massachusetts Declaration of Rights, because a refusal is testimonial.

Evidence that a driver refused field sobriety tests is likewise inadmissible because the refusal is testimonial, even though performing the tests produces physical evidence. Commonwealth v. McGrail, 419 Mass. 774, 779-780 (1995).

In Commonwealth v. Blais, 428 Mass. 294, 299 & n.3 (1998), the Supreme Judicial Court later disapproved McGrail to the extent it suggested that a driver has no legal obligation to perform the tests. The court in Blais held that police may request field sobriety tests during a lawful stop based on reasonable suspicion of OUI and need not advise the driver that the tests may be refused. The Article 12 protection concerns the admissibility of the refusal, not a general privilege to withhold physical evidence.

The Field Sobriety Tests

The standardized field sobriety tests are the horizontal gaze nystagmus test, the walk and turn, and the one leg stand. The National Highway Traffic Safety Administration designed the tests to classify a driver’s blood alcohol at or above .08, at the accuracy rates claimed by the agency. The walk and turn is scored on two or more of eight clues, the one leg stand on two or more of four clues, and the horizontal gaze nystagmus test on four or more of six clues.

The National Highway Traffic Safety Administration manual for the tests does not contain a failing score. The word “failed” is courtroom shorthand, not a result the test produces. An officer should not testify that a driver passed or failed.

The horizontal gaze nystagmus test is different from the walk and turn and the one leg stand. The horizontal gaze nystagmus test is based on a scientific proposition about involuntary eye movement, so the Commonwealth must present expert testimony and a scientific foundation before a jury may hear evidence of the test. Commonwealth v. Sands, 424 Mass. 184 (1997). The walk and turn and the one leg stand are within a juror’s common experience and do not require an expert.

An officer who watched the driver may give an opinion on the driver’s level of sobriety. The officer may not give an opinion on the ultimate question, which is whether the driver was under the influence or whether alcohol impaired the ability to operate. Commonwealth v. Canty, 466 Mass. 535 (2013). The firm’s page on cross-examining the field sobriety opinion covers cross-examination of the officer on the instructions given, the conditions of the roadside, and the scoring. The firm explains the tests and the science on its field sobriety test defense page.

Operating Under the Influence of Drugs

The field sobriety tests were developed for alcohol. There is no scientific consensus that performance on the tests correlates with marijuana use or impairment. In a marijuana case, the officer may describe performance only as roadside assessments of balance, coordination, mental acuity, and other driving-related skills. The officer may not testify that the driver passed or failed or that the assessments established marijuana impairment. The officer also may not offer a lay opinion that the driver was intoxicated by marijuana.

The jury may consider the officer’s observations of the roadside assessments with the other evidence, but roadside-assessment performance alone cannot support a conviction. Commonwealth v. Gerhardt, 477 Mass. 775, 776-777, 783-785 (2017). The firm addresses the remaining evidence issues on its OUI drugs and marijuana defense page.

The Criminal Case and Registry License Actions

Different rules apply to the criminal prosecution and a Registry license action. The criminal case proceeds in the District Court or Boston Municipal Court, where the Commonwealth must prove the charged offense. In an alcohol OUI case, refusal of a chemical test for alcohol or a qualifying blood alcohol result may cause a Registry suspension before disposition. A later court disposition may cause an additional license consequence. A refusal suspension becomes effective when the driver receives the officer’s notice.

An immediate threat suspension under M.G.L. c. 90, § 22(a) is separate from the refusal suspension, the result-based suspension, and any license consequence of a court disposition. Police may ask the RMV to suspend a person’s license immediately and indefinitely based on the reported driving conduct, even without an arrest, refusal of the breathalyzer, qualifying test result, guilty plea, or conviction.

The chemical-test suspensions ordinarily do not arise without an arrest. The police can still submit an immediate threat request when an OUI investigation ends in a summons rather than an arrest. The Massachusetts immediate threat license suspension guide explains the police request, RMV hearing, records, pending criminal case, and appeals. The immediate threat FAQs provide concise answers.

The police ordinarily take the license of a driver whose breath test final analysis is .08 or greater. The suspension lasts until disposition of the offense, but no more than 30 days. G.L. c. 90, § 24(1)(f).

A suspension based on a court disposition is separate from the immediate result-based suspension. Attorney Serpa handles the criminal case and advises on the Registry process, but he does not appear with clients at the Registry. The firm addresses the principal refusal and result-based rules in its Massachusetts OUI FAQs and limited-license eligibility in its hardship-license guide.

Penalties by Offense Number

A first offense under G.L. c. 90, § 24(1)(a)(1) is punishable by a fine of not less than $500 and not more than $5,000, by up to two and one half years in a house of correction, or both. A first offense is also subject to a mandatory $250 head injury assessment and a $50 assessment.

For an OUI conviction revocation imposed without a disposition under G.L. c. 90, § 24D, the one-year revocation applies when the person has no qualifying prior. The first hardship-hearing date is three months after conviction. Section 24 provides a second hearing date after six months.

At three months, Section 24 permits a request for a license for employment or education. At six months, Section 24 permits a request for a limited license on general hardship grounds. Under the current Registry of Motor Vehicles criteria, medical treatment or another supported purpose can support the later request. The applicant must document the need, explain why public transportation cannot meet it, and show that the causes of the current and prior violations have been addressed or brought under control. Any approved hardship license allows driving during the same fixed 12-hour period each day. Approval remains discretionary.

Most first offenders resolve the case under the alternative disposition in G.L. c. 90, § 24D. A person is eligible as a true first offender. A person whose single prior like offense was disposed of by a court of the Commonwealth or any other jurisdiction 10 years or more before the date of the new offense is also eligible once in a lifetime.

Under a § 24D disposition, the judge places an eligible person on probation for up to two years and orders participation in the driver-alcohol education or treatment program specified by the statute. The license suspension is ordinarily 45 to 90 days, but it is 210 days if the person was under 21 when the offense was committed.

Upon entering the required program, the person may immediately apply to the Registry for consideration of a hardship license. The Registry decides in its discretion whether to issue the license. The Registry may make an ignition interlock device a condition of the hardship license if the blood alcohol percentage was .15 or greater. Section 24D is unavailable if the incident caused serious personal injury or death.

Under the ordinary second-offense sentencing provision, a second offense is punishable by both a fine and imprisonment. The fine is not less than $600 and not more than $10,000. The term of imprisonment is not less than 60 days and not more than two and one-half years in a house of correction. The sentence may not be reduced below 30 days, and at least 30 days must be served. G.L. c. 90, § 24(1)(a)(1).

As an alternative to imprisonment, the judge may place a second offender who consents on probation for two years with a mandatory 14 day residential alcohol treatment program, after making written findings. G.L. c. 90, § 24(1)(a)(4). The Registry ordinarily revokes the license for two years after a second-offense conviction.

A person whose only prior offense is 10 years or more old may receive the first-offender type disposition under G.L. c. 90, § 24D. The resulting license suspension is ordinarily 45 to 90 days rather than two years, but it is 210 days if the person was under 21 when the new offense was committed. Commonwealth v. Cahill, 442 Mass. 127 (2004). The firm explains this limited second disposition on its Cahill second offense page.

The third and later offenses are felonies. A third offense is punishable by a fine of not less than $1,000 and not more than $15,000 and by imprisonment. The term of imprisonment is two and one-half to five years in state prison or 180 days to two and one-half years in a house of correction. The sentence may not be reduced below 150 days, and at least 150 days must be served.

The Registry revokes the license for eight years after a third-offense conviction. After two years, the person may request a license for employment or education. After four years, the person may request a limited license on general hardship grounds. Either request remains subject to the Registrar’s discretion.

A fourth offense is punishable by a fine of not less than $1,500 and not more than $25,000 and by imprisonment. The term of imprisonment is two and one half to five years in state prison or two to two and one half years in a house of correction. At least one year must be served.

The Registry revokes the license for ten years after a fourth-offense conviction. After five years, the person may request a license for employment or education. After eight years, the person may request a limited license on general hardship grounds. Either request remains subject to the Registrar’s discretion.

A fifth offense is punishable by a fine of not less than $2,000 and not more than $50,000 and by imprisonment. The term of imprisonment is two and one half to five years in state prison or two and one half years in a house of correction. At least two years must be served.

The Registry revokes the license for life after a fifth-offense conviction. The ordinary hardship procedure provides no hearing for a person with a fifth-offense conviction. Massachusetts law requires the sentencing calculation to include qualifying prior offenses over the driver’s lifetime, subject to the narrow additional Section 24D disposition described above.

Melanie’s Law requires an ignition interlock device for repeat offenders. G.L. c. 90, § 24½. The interlock requirement applies to a person whose license is suspended for an OUI conviction or program assignment in the Commonwealth or any other jurisdiction and who has a prior such conviction or assignment. A person subject to the interlock requirement cannot obtain a new or restored license unless a certified device is installed on every vehicle the person owns, leases, and operates. The device must remain installed for two years.

For a second-offense revocation without a Section 24D disposition, the person may request a license for employment or education after one year. After 18 months, the person may request a limited license on general hardship grounds. Either request remains subject to the Registrar’s discretion. An ignition interlock device is mandatory for any approved hardship license.

A person receiving the once-in-a-lifetime Section 24D disposition described above may instead apply for hardship consideration immediately after entering the program. The person has a qualifying prior offense, so the repeat-offender ignition-interlock requirement still applies. Operating in violation of an ignition-interlock restriction is a separate crime under G.L. c. 90, § 24S.

A prior offense can come from another state. Under G.L. c. 90, § 24, a prior offense includes a conviction, or a court ordered program assignment, entered by a court of the Commonwealth or any other jurisdiction for a like violation. An out-of-state OUI conviction counts as a prior offense.

An out-of-state action that was purely administrative, such as an implied consent refusal suspension entered by a motor vehicle agency with no court disposition, is neither a conviction nor a court assignment. A purely administrative out-of-state action therefore does not count as a prior offense. Similarly, a Massachusetts OUI conviction or program can count as a prior offense if a driver is charged with a subsequent offense in another state.

Serious Injury, Death, and a Child in the Vehicle

G.L. c. 90, § 24L contains two OUI serious-bodily-injury offenses. Subsection (1) requires proof that the defendant operated under the influence or at the charged blood alcohol percentage, operated negligently or recklessly, and caused serious bodily injury. The subsection (1) offense is a felony punishable by a fine of not more than $5,000 and either two and one-half to ten years in state prison or six months to two and one-half years in a house of correction. At least six months must be served.

Subsection (2) requires proof that the OUI operation caused serious bodily injury, but it does not require separate negligent or reckless operation. The subsection (2) offense is punishable by up to two and one-half years in a house of correction, a fine of at least $3,000, or both. For both offenses, serious bodily injury means an injury that creates a substantial risk of death or causes total disability, loss, or substantial impairment of a bodily function for a substantial period. A conviction causes a two-year license revocation.

G.L. c. 90, § 24G(a) applies when OUI operation, together with negligent or reckless operation, causes a death. The § 24G(a) offense is punishable by a fine of not more than $5,000 and either two and one-half to fifteen years in state prison or one to two and one-half years in a house of correction. At least one year must be served.

Section 24G(b) also contains an OUI motor vehicle homicide offense. The Commonwealth must prove that operation under the influence or at .08 or greater caused the death, but it need not prove separate negligent or reckless operation. The offense is punishable by a fine of $300 to $3,000, incarceration for 30 days to two and one-half years, or both. A fine without incarceration is therefore authorized.

The Registry ordinarily revokes the license for 15 years after a first conviction for homicide by motor vehicle under § 24G and for life after a subsequent conviction. Section 24R can require lifetime revocation based on qualifying prior convictions.

G.L. c. 90, § 24V applies when a child who is 14 years old or younger is in the vehicle during a listed OUI offense. Section 24V does not require proof that the operation caused an injury. A first offense is punishable by a fine of $1,000 to $5,000, 90 days to two and one-half years in a house of correction, and a one-year license suspension. The sentence is consecutive to the sentence for the underlying offense. The Commonwealth can also charge reckless endangerment of a child under G.L. c. 265, § 13L for the same incident.

The Commonwealth need not prove the same elements for each charge. The OUI-causing-serious-bodily-injury offenses under Section 24L and the homicide-by-motor-vehicle offenses under Section 24G require causation. The felony provisions in Sections 24L(1) and 24G(a) also require negligent or reckless operation, while the child-endangerment offense under Section 24V requires the child’s presence rather than causation. The firm addresses the related charges on its page about motor vehicle homicide and operating to endanger.

The Defense of a Massachusetts OUI Case

The defense of an OUI case begins with an examination of the stop. The police need a lawful reason to stop the vehicle, a lawful basis for an exit order, and a lawful basis for each step that follows. The defense examines the reason for the stop, the observations the officer recorded, the instructions given before the field sobriety tests, the conditions of the roadside, and the foundation of the breath test final analysis.

A judge who finds that the stop or a later step was unlawful can suppress the officer’s observations and any other evidence the police obtained after the unlawful stop or step. A motion to suppress can therefore result in dismissal of the case. The judge can end the case before jury deliberations by allowing a motion for a required finding of not guilty if the Commonwealth has not proven one or more of the elements discussed above.

At trial, Attorney Serpa cross-examines the officer about the observations, the field-test scoring, and the breath test final analysis, if applicable. He prepares the examination from the case-specific evidence rather than a fixed script. The firm addresses the governing cross-examination principles on its cross-examination page.

An OUI complaint often includes additional offenses, usually operating to endanger, negligent or reckless operation, or operating after a suspension. Many OUI arrests also begin at a sobriety checkpoint, which has its own rules.

Some drivers arrested for OUI hold a license to carry and have a loaded gun in the car. A driver arrested for OUI with a loaded gun in the car can also be charged with carrying a loaded firearm while under the influence under G.L. c. 269, § 10H. A judge or jury can convict the driver of carrying a loaded firearm while under the influence even after acquitting the driver of the OUI.

Who Attorney Serpa Represents

Attorney Serpa represents people charged with operating under the influence across Greater Boston, from a first offense to a subsequent offense, and in cases that involve a breath test, a refusal, drugs, or a serious injury. The office also represents those who face added consequences from an OUI, including college and university students, licensed professionals, and non-citizens. Clients who travel to Canada for work or family also face the risk that a Canadian border officer will refuse entry after an OUI.

The office answers questions about the criminal case and the Registry consequences together, so a client understands both from the start. Contact Serpa Law Office at 617.936.0201 for a free, confidential consultation. Serpa Law Office has offices at 20 Park Plaza, Suite 400A, in Boston and 500 Victory Road, Suite 400A, in Quincy.

Massachusetts Courts Where Attorney Serpa Tries These Cases

Attorney Serpa tries OUI cases in the Boston Municipal Court and in the District Courts of Greater Boston, including the courts in Quincy, Dedham, Cambridge, Somerville, Malden, Framingham, and the surrounding communities. He has tried cases in the Greater Boston courts since 1995. The firm keeps a guide to the Massachusetts District Courts. Attorney Serpa’s background appears on his profile.

Related Serpa Law Office Resources

Serpa Law Office organizes its OUI and related motor vehicle pages in the Massachusetts OUI and motor vehicle defense hub.

Last Reviewed: August 2026