Massachusetts DUI Laws

"OUI" stands for Operating Under the Influence, and it is the term Massachusetts uses for impaired-driving offenses in M.G.L. c. 90 §24(1)(a)(1), in court papers, and in Registry of Motor Vehicles (RMV) correspondence. Functionally, OUI is Massachusetts's version of what other states call DUI ("driving under the influence") or DWI ("driving while intoxicated"). The conduct prohibited is the same idea — operating a motor vehicle while impaired by alcohol or by certain drugs. Under §24(1)(a)(1), the statute reaches operation while having a blood alcohol level of 0.08 or greater, while under the influence of intoxicating liquor, or while under the influence of marijuana, narcotic drugs, depressants, stimulants, or toxic vapors as defined in M.G.L. c. 270 §18. If your citation, court paperwork, or RMV notice uses "OUI," it refers to this Massachusetts §24 charge.

Massachusetts's per-se BAC threshold is 0.08 or greater under M.G.L. c. 90 §24(1)(a)(1), but the same statute also prohibits operating "under the influence of intoxicating liquor" without any per-se number — a sub-0.08 driver can still be charged on impairment evidence alone. These two prongs run side by side. Under the per-se prong, the Commonwealth proves the case by showing a chemical test reading of 0.08 or greater at the time of operation. Under the impairment-based prong, the Commonwealth proves the case by showing impairment using observational evidence (driving conduct, field-sobriety performance, officer testimony) regardless of the BAC number. The same §24(1)(a)(1) statute also reaches OUI-Drugs: operating while under the influence of marijuana, narcotic drugs, depressants, or stimulants as defined in M.G.L. c. 94C §1, or while under the influence of toxic vapors as defined in M.G.L. c. 270 §18. There is no per-se number for the drug prong — the test is impairment, not the substance's recreational legal status. The fact that recreational marijuana use is legal in Massachusetts does not affect whether OUI-Drugs charges apply; the OUI-Drugs prong reaches impairment by marijuana the same way it reaches impairment by other listed substances. Commercial drivers face a lower threshold of 0.04 or greater under M.G.L. c. 90F (commercial driver licensing), and drivers under 21 face a 0.02 administrative threshold under M.G.L. c. 90 §24P — see ma-faq-3.

Massachusetts's under-21 administrative BAC threshold is 0.02 or greater under M.G.L. c. 90 §24P. An under-21 driver who registers 0.02+ on a chemical test (or refuses testing) following an OUI-related arrest faces a 180-day RMV license suspension (1 year if the driver is under 18), imposed by the Registrar of Motor Vehicles independent of the criminal case. A first-time under-21 offender age 18 or older may consent to a Department of Public Health Youth Alcohol Program (YAP) and, upon program entry, have the 180-day suspension waived by the registrar. An under-18 first-time offender's 1-year suspension is reduced to 180 days upon program entry under §24P (the heightened under-18 administrative track imposes a 180-day floor that program entry does not waive entirely). On failure to complete the program, the registrar re-imposes the full statutory suspension — 180 days for an 18-or-older driver, or 1 year for an under-18 driver. The under-21 administrative track does not displace the standard adult OUI criminal charge. M.G.L. c. 90 §24(1)(a)(1)'s 0.08 per-se threshold and impairment-based prong both apply to under-21 drivers on the criminal-court side. An under-21 driver with a 0.05 BAC is not safe from criminal OUI charge; both tracks can run in parallel.

A first-offense OUI in Massachusetts carries a base statutory range under M.G.L. c. 90 §24(1)(a)(1) of a fine of $500–$5,000 and up to 2½ years in a house of correction, plus a 1-year license revocation under §24(1)(b) and §24(1)(c)(1). These ranges represent the straight-conviction path. Surcharges and assessments under §24D and M.G.L. c. 90C add to the actual disposition cost beyond the $500 statutory floor. In practice, most first-offense defendants who plead resolve through the §24D Driver Alcohol Education Program rather than through straight conviction — see ma-faq-11 for §24D details. Under §24D, the disposition typically involves 1–2 years of probation, completion of an alcohol-education program, and a 45-to-90-day license suspension (210 days if under 21) in lieu of the 1-year revocation. §24D also imposes the same fine range as the straight-conviction path, plus a head-injury-fund surcharge. A second-offense defendant whose prior OUI is 10 or more years before the date of the new offense may be eligible at judicial discretion for the §24D second-chance first-offender carve-out, in which case the disposition resolves under the first-tier framework above (called a "Cahill disposition" after Commonwealth v. Cahill) — see ma-faq-7 for the lifetime-lookback context and ma-faq-11 for the §24D mechanics. If the OUI arrest involved a chemical test reading 0.15 or greater, the Registrar may attach an ignition interlock device (IID) as a condition of any hardship license under §24(1)(c)(1); this is hardship-side, not a tier-level mandate at first offense — see ma-faq-14.

A second-offense OUI in Massachusetts (one prior OUI conviction or §24D assignment, lifetime lookback) carries a fine of $600–$10,000, 30-day statutory mandatory minimum jail under M.G.L. c. 90 §24(1)(a)(1) with a 2½-year ceiling, and a 2-year license revocation under §24(1)(c)(2). Reinstatement requires completing an RMV reinstatement process with re-testing, which is why the §24 statute uses revocation language rather than suspension at this tier. The 30-day mandatory minimum is statutory but is subject to alternative dispositions including 14-day in-patient programs, split sentences, and §24D second-chance treatment when the prior is 10 or more years before the date of the new offense. Whether any of these alternatives is available is fact-specific and turns on judicial discretion and the prior-OUI date. Ignition interlock is mandatory at second offense and beyond under Melanie's Law, codified at M.G.L. c. 90 §24½. IID is required for the duration of the conditional hardship-license period and for an additional 2 years following full-license reinstatement — see ma-faq-14. A second-offense defendant whose prior OUI is 10 or more years before the date of the new offense may be eligible at judicial discretion for the §24D second-chance first-offender carve-out (codified at §24D itself; commonly called a "Cahill disposition" after Commonwealth v. Cahill). Under this carve-out, the case resolves as first-tier — 1–2 years probation, 45–90-day license suspension, alcohol-education program — instead of the second-offense ranges above. The carve-out is a once-in-a-lifetime eligibility; any subsequent OUI counts every prior under §24(1) for sentencing. See ma-faq-7 and ma-faq-11.

A Massachusetts OUI becomes a felony at the third lifetime offense under M.G.L. c. 90 §24(1)(a)(1), and on a first offense whenever the operation causes serious bodily injury under §24L or causes death under §24G. These are two independent paths to felony exposure; either can apply on its own. Prior-count path. Under §24(1)(a)(1), a third OUI carries a fine of $1,000–$15,000, imprisonment of 150 days to 5 years in the state prison or 6–2½ years in a house of correction, and a 150-day mandatory minimum. A fourth carries $1,500–$25,000 and 1–5 years state prison (1-year mandatory minimum). A fifth carries $2,000–$50,000 and 2–5 years state prison (2-year mandatory minimum). Penalties continue escalating through ninth-and-subsequent (10-year ceiling, 4-year mandatory minimum). Each tier has its own §24(1)(a)(1) sub-clause; the multi-class felony cascade is structurally distinct from the single-tier elevation pattern in some other states. License-action consequences scale in parallel — see ma-faq-8. Injury / homicide path. Felony exposure attaches on a first offense whenever OUI operation causes harm: - §24G(a) — motor vehicle homicide as a compound offense: OUI (BAC ≥ 0.08 or under the influence of intoxicating liquor / drugs / vapors) AND reckless or negligent operation, AND causing death — state prison 2½–15 years (1-year mandatory minimum, no probation/parole/furlough/CWOF) or 1–2½ years house of correction; fine ≤ $5,000. - §24G(b) — motor vehicle homicide as a disjunctive misdemeanor, reaching either (i) operating with BAC 0.08 or greater or under the influence of intoxicating liquor / drugs / vapors AND causing death (no recklessness or negligence required), OR (ii) operating negligently endangering public safety AND causing death (no OUI element required): jail/house of correction 30 days–2½ years; fine $300–$3,000. - §24L(1) — OUI causing serious bodily injury by reckless or negligent operation while OUI: state prison 2½–10 years (6-month mandatory minimum, no probation/parole/furlough/CWOF) or 6 months–2½ years house of correction; fine ≤ $5,000. - §24L(2) — OUI causing serious bodily injury without the reckless/negligent element: jail/house of correction up to 2½ years; fine ≥ $3,000. §24L(3) defines "serious bodily injury" as bodily injury creating a substantial risk of death or involving total disability or substantial impairment of some bodily function for a substantial period of time — this is a statutory term, narrower than colloquial "serious injury." §24R lifetime-revocation overlay. §24R imposes lifetime license revocation as an RMV-side consequence following certain multi-conviction histories (e.g., a §24G(a) conviction with a prior §24(1)(a) conviction, or vice versa). This is distinct from the §24(1)(a)(1) felony classification — §24R operates on the license-action surface, not the criminal-court surface. See ma-faq-8 for the post-conviction license action.

Massachusetts uses a lifetime lookback for OUI prior-offense counting. Under M.G.L. c. 90 §24(1)(a)(1), every prior OUI conviction or §24D Driver Alcohol Education assignment counts toward repeat-offender status regardless of how long ago — there is no time window. Melanie's Law (St. 2005, c. 122) abolished the prior 10-year window and embedded the lifetime rule in §24(1)(a)(1)'s offense-counting language. The lifetime rule has one practical carve-out at sentencing: the §24D second-chance first-offender carve-out, available at judicial discretion when the prior OUI conviction is 10 or more years before the date of the new offense. Under §24D itself, a defendant with a single prior OUI conviction or §24D assignment that occurred 10 or more years before the new offense date may be sentenced as a first-offender under §24D, once in a lifetime. This is commonly called a "Cahill disposition" after Commonwealth v. Cahill, which held the RMV must honor the court's §24D second-offense disposition for license-action purposes. The carve-out is an eligibility carve-out within §24D itself, not an exception to the lookback rule — the prior is still counted; the §24D pathway is just made available at the court's discretion. After a second-chance disposition, all priors are counted under §24(1) for any subsequent OUI. See ma-faq-11 for §24D details. A CWOF counts as a prior conviction for OUI lifetime-lookback purposes under §24(1)(a)(1) and Melanie's Law, even though it does not count as a conviction for many other purposes (employment background checks, sealing eligibility, civil consequences). For OUI counting, a CWOF on a prior OUI case treats the defendant as having a prior conviction at the next OUI — most CWOF dispositions in OUI cases happen as part of a §24D assignment, and the §24D assignment itself is independently a counted prior under §24(1)(a)(1)'s "convicted of … or assigned to" language. See ma-faq-12 for the CWOF mechanism. Out-of-state DUI/DWI/OWI/OVI convictions count toward Massachusetts lifetime lookback when the underlying offense is sufficiently similar to §24(1)(a)(1) OUI — a statutory-comparison test, not an automatic count of every out-of-state conviction. Massachusetts is a member of the Driver License Compact under M.G.L. c. 90 §30B, which obligates the RMV to receive reciprocal reporting from member states. The similarity test asks whether the out-of-state offense's elements are sufficiently similar to Massachusetts's OUI elements; the answer is fact-specific and turns on the comparison statute.

Post-conviction license action in Massachusetts escalates by lifetime offense count under M.G.L. c. 90 §24(1)(b) and §24(1)(c). After a first OUI conviction, the license is revoked for 1 year (§24(1)(c)(1)), with hardship eligibility after 3 months (employment or education) or 6 months (general) — though most first-offense defendants resolve through §24D, in which case the license is suspended 45–90 days (210 days if under 21) instead. After a second offense, the license is revoked for 2 years (§24(1)(c)(2)), hardship after 1 year (employment or education) or 18 months (general). After a third, revocation runs 8 years (§24(1)(c)(3)), hardship after 2 years / 4 years. After a fourth, 10 years (§24(1)(c)(3½)), hardship after 5 years / 8 years. After a fifth or subsequent, lifetime revocation (§24(1)(c)(3¾)) — no hardship. Massachusetts uses revocation language rather than suspension at second-and-beyond because the RMV requires a reinstatement process (re-testing and application) at the end of the revocation period; the license is not automatically restored. Reinstatement at higher tiers may also require completion of programs and IID compliance. §24R additionally imposes lifetime revocation in certain multi-conviction histories — for example, a §24G(a) OUI homicide conviction with a prior §24(1)(a) OUI conviction. §24R is an RMV-side overlay distinct from the §24(1)(c) cascade above; the same offender can face a §24(1)(c)(3¾) lifetime revocation and a §24R lifetime revocation on the same record without conflict. Hardship-license eligibility windows can materially shorten the practical no-driving period — see ma-faq-10. Pre-trial license consequences run separately — see ma-faq-9 (30-day BAC track) and ma-faq-13 (refusal track).

Massachusetts has a two-track pre-trial license consequence that surprises many newly-arrested drivers. If the chemical breath test reads 0.08 or greater, M.G.L. c. 90 §24(1)(f)(2) imposes a pre-trial administrative suspension by the Registrar of Motor Vehicles. The suspension runs immediately, independently of the criminal case outcome, until disposition of the underlying criminal case, capped at 30 days by statute. If the case resolves within 30 days (e.g., a §24D first-offender disposition or a dismissal), the suspension ends earlier; if disposition has not occurred within 30 days, the suspension lifts at the 30-day mark by operation of statute. The suspension is administrative in nature — not a court-ordered penalty and does not require a conviction. The 30-day rule applies when (1) the breath test reads 0.08 or greater (or 0.02+ for under-21 drivers), and (2) the driver is age 21+, and (3) the case has not been resolved by a §24D first-offender disposition that subsumes the suspension. A §24D disposition that resolves the case shortcuts the 30-day pre-trial period because §24D imposes its own 45–90-day license-loss schedule that absorbs the pre-trial suspension. The 30-day BAC-track suspension is distinct from the refusal track — if the driver refused testing instead of submitting and registering 0.08+, the §24(1)(f)(1) refusal-suspension applies, which carries 180 days to lifetime depending on prior count and age (see ma-faq-13). The two tracks are alternative paths, not stacked. A driver may request an RMV hearing to challenge the 30-day suspension, and may also seek court-side procedural recourse for a hearing within 10 days before the court of original jurisdiction under M.G.L. c. 90 §24N (the 10-day court hearing is limited to whether a comparison blood test taken under §24(1)(e) shows a sub-0.08 reading). §24N is the citation conventionally used for the 10-day court-side recourse pathway; technically, §24N's recourse text governs §24N-imposed suspensions, while §24(1)(g) provides parallel RMV-side recourse for §24(1)(f) suspensions. 540 CMR 11.00 governs RMV refusal-hearing procedure on the parallel refusal track.

Massachusetts allows hardship licenses (sometimes called "Cinderella licenses") during a license suspension or revocation, subject to RMV discretion. A hardship license is a discretionary RMV grant, not an entitlement — eligibility for the window does not guarantee approval, and the RMV reviews each application against employment, family, and medical-need criteria. Eligibility windows per tier, per RMV-published guidance and M.G.L. c. 90 §24(1)(c): - First offense, 1-year revocation: hardship eligibility after 3 months (employment or education) or 6 months (general). After a §24D disposition (45–90-day suspension), hardship is generally available immediately upon completion of pre-disposition steps. - Second offense, 2-year revocation: hardship after 1 year (employment or education) or 18 months (general). IID is mandatory as a condition of any hardship grant under M.G.L. c. 90 §24½. - Third offense, 8-year revocation: hardship after 2 years (employment or education) or 4 years (general). IID mandatory. - Fourth offense, 10-year revocation: hardship after 5 years (employment or education) or 8 years (general). IID mandatory. - Fifth or subsequent offense, lifetime revocation: no hardship eligibility. Lifetime revocation under §24R likewise carries no hardship eligibility. A hardship license is geographically and temporally restricted — it permits driving for specified purposes (typically work, medical appointments, child care, education) within defined hours, not general driving privileges. Failure to comply with hardship-license restrictions or IID conditions can result in revocation of the hardship grant and reinstatement of the underlying suspension. First-offense hardship applicants whose chemical-test BAC was 0.15 or greater at arrest may have IID imposed on the hardship license under §24(1)(c)(1) at the Registrar's discretion. Second-offense and beyond, IID-on-hardship is categorical under Melanie's Law — see ma-faq-14.

The §24D Driver Alcohol Education Program (commonly called the "24D disposition" or the "Brennan Program") is the dominant first-offender pathway for Massachusetts OUI cases. It is codified at M.G.L. c. 90 §24D and operates as an alternative disposition rather than a separate offense — the defendant pleads or admits, the court assigns the §24D program in lieu of imposing the full §24(1)(a)(1) penalty range, and the case resolves with probation, alcohol-education programming, and a shorter license loss. Eligibility. §24D applies in two distinct sub-cases: 1. Default first-offender treatment. A defendant charged with §24(1)(a)(1) OUI who has never been convicted of OUI and has never been assigned to an alcohol or controlled-substance education, treatment, or rehabilitation program for a like offense. Eligibility is at judicial discretion — the court must accept the disposition. 2. Second-chance first-offender ("Cahill") treatment. A defendant charged with OUI who has a single prior OUI conviction or §24D assignment 10 or more years before the date of the new offense, once in a lifetime. Eligibility is at judicial discretion under §24D itself; Commonwealth v. Cahill held the RMV must honor the court's §24D second-offense disposition for license-action purposes. Any subsequent OUI after a second-chance disposition counts every prior under §24(1) for sentencing — see ma-faq-7 and ma-faq-5. The Cahill defendant retains a prior OUI conviction (that's what makes them a Cahill candidate) and is therefore a multi-offender for §24½ purposes; see the IID-on-hardship bullet below. Program elements. Under §24D, the disposition typically includes: - Probation for up to 2 years (commonly 1 year). - Driver Alcohol Education Program (DAEP) — a 16-week alcohol-education curriculum administered through Massachusetts Department of Public Health-approved providers. For under-21 defendants whose chemical-test BAC was 0.20 or greater, the assigned program is the 14-day in-home second-offender program rather than the standard DAEP. - License loss of 45–90 days (210 days if under 21), shorter than the §24(1)(b) 1-year revocation that would apply on straight conviction. - The §24(1)(a)(1) fine range still applies ($500–$5,000), plus a head-injury-fund surcharge and other assessments. - Possible IID-on-hardship if chemical-test BAC was 0.15 or greater (§24(1)(c)(1) discretion). For Cahill / second-chance dispositions, the defendant has a prior OUI conviction or §24D assignment and is therefore a multiple OUI offender under M.G.L. c. 90 §24½ — §24½'s categorical IID mandate applies for the hardship-license period plus 2 years following full-license reinstatement. The Cahill defendant's structural placement at first-tier (45–90-day suspension under §24D) does not displace §24½'s multi-offender IID mandate; the two operate independently. §24D is most often resolved as a CWOF (Continued Without a Finding) — see ma-faq-12 for the CWOF mechanism. A CWOF on a §24D disposition counts as a prior OUI for lifetime-lookback purposes under §24(1)(a)(1) and Melanie's Law.

A Continued Without a Finding (CWOF) is a Massachusetts plea posture under M.G.L. c. 278 §18 in which the defendant admits sufficient facts to warrant a finding of guilt, but the court continues the case without entering a guilty finding for a probation period. Successful completion of probation results in dismissal of the case; the defendant has no conviction for most purposes (employment background checks, sealing eligibility, civil consequences). Probation violation can result in conversion of the CWOF to a guilty finding with the original §24(1)(a)(1) penalty range applying. For OUI cases specifically, however, a CWOF counts as a prior conviction for OUI lifetime-lookback purposes under M.G.L. c. 90 §24(1)(a)(1) and Melanie's Law (St. 2005, c. 122), even though it does not count as a conviction for many other purposes. A defendant who took a CWOF on a first OUI and is later arrested again is treated as a second-offense defendant under §24(1)(a)(1)'s offense-counting cascade. This holds whether the CWOF was issued as part of a §24D Driver Alcohol Education assignment (the modal §24D disposition path) or as a standalone CWOF — §24(1)(a)(1)'s "convicted of … or assigned to an alcohol or controlled substance education, treatment or rehabilitation program" language covers both pathways. See ma-faq-7 for the lifetime-lookback context and ma-faq-11 for §24D details. CWOF is not available for certain enhanced offenses. §24G(a) (motor vehicle homicide compound offense), §24L(1) (OUI causing serious bodily injury by reckless or negligent operation while OUI), and §24V (child endangerment while operating under the influence) each contain express statutory bars: "Prosecutions commenced under this section shall neither be continued without a finding nor placed on file" (§24G(a)); parallel bars in §24L(1) and §24V. For these offenses, the CWOF mechanism is foreclosed by statute. See ma-faq-6 (felony path) and the aggravators section of this page for details. CWOF dispositions on OUI cases are also reported to the Driver License Compact through the RMV under M.G.L. c. 90 §30B, so out-of-state home jurisdictions of Massachusetts CWOF defendants typically receive notice of the disposition.

Refusing a chemical breath or blood test in Massachusetts triggers an administrative license suspension by the Registry of Motor Vehicles under M.G.L. c. 90 §24(1)(f)(1) — Massachusetts's implied-consent statute. The suspension is administrative, not criminal: it runs whether or not the underlying OUI charge results in conviction, and refusal itself is not a separate crime in Massachusetts. Tiered durations. Refusal-suspension lengths split along three axes — lifetime prior count, age, and prior-offense type: - 180 days — driver age 21+, no prior OUI conviction or §24D assignment, first refusal. - 3 years — driver under 21 with a first refusal, OR driver age 21+ with one prior OUI conviction or §24D assignment. - 5 years — driver with two prior OUI convictions or §24D assignments (regardless of age). - Lifetime — driver with three or more prior OUI convictions or §24D assignments (regardless of age). Conviction-type escalators (overlay on the count-and-age matrix). A driver who refuses a chemical test after a prior §24L (OUI causing serious bodily injury) conviction faces a 10-year suspension under §24(1)(f)(1), regardless of the count-and-age tier. A driver who refuses after a prior §24G(a) or §24G(b) (motor vehicle homicide) conviction or a §13½ ch. 265 conviction faces a lifetime revocation under §24(1)(f)(1), regardless of the count-and-age tier. These escalators are imposed by the registrar in addition to any consecutively-running suspension following the new criminal disposition. The lookback for counting priors at the refusal track is lifetime, matching the §24(1)(a)(1) OUI-conviction lookback (see ma-faq-7). Out-of-state DUI/DWI/OWI/OVI convictions sufficiently similar to §24(1)(a)(1) count. RMV-side recourse. A driver may request an RMV hearing within 15 days of suspension under 540 CMR 11.00; the hearing is limited to three issues: (1) whether the police officer had reasonable grounds to believe the driver was OUI, (2) whether the driver was placed under arrest, and (3) whether the driver in fact refused the test. Negative finding on any one of the three restores the license. Court-side recourse. A driver may also request a hearing within 10 days before the court of original jurisdiction under M.G.L. c. 90 §24N, on the same three issues. (§24N is the citation conventionally used for the 10-day court-side recourse pathway; technically, §24N's recourse text governs §24N-imposed suspensions, while §24(1)(g) provides parallel RMV-side recourse for §24(1)(f) suspensions. §24N is not itself the implied-consent statute; the implied-consent rule is at §24(1)(f)(1).) Refusal of a chemical test is not admissible against the defendant in any civil or criminal proceeding. M.G.L. c. 90 §24(1)(e) provides a broad statutory evidentiary bar: "evidence that the defendant failed or refused to consent to such test or analysis shall not be admissible against him in a civil or criminal proceeding." This bar reaches all uses of chemical-test refusal evidence against the defendant — including but not limited to as consciousness-of-guilt evidence — across both civil and criminal proceedings. Commonwealth v. McGrail, 419 Mass. 774 (1995), extends a parallel constitutional bar (under art. 12 of the Massachusetts Declaration of Rights) to field-sobriety-test refusal, treating refusal as compelled testimonial evidence. Massachusetts is distinctive on this point — most other states permit refusal as evidence at trial. The administrative refusal suspension under §24(1)(f)(1) is unaffected by these evidentiary bars and applies regardless of the criminal-case outcome. The 30-day pre-trial breath-test track at §24(1)(f)(2) is a separate alternative path (when the driver submits and registers 0.08+), not a stack with the refusal suspension — see ma-faq-9.

Massachusetts's ignition interlock device (IID) regime under Melanie's Law (St. 2005, c. 122) is codified at M.G.L. c. 90 §24½. The statute makes IID mandatory for multiple OUI offenders — anyone with two or more lifetime OUI convictions or §24D Driver Alcohol Education assignments. Per-tier: - First offense: IID is not a tier-level mandate. §24½'s categorical mandate reaches multiple-offenders only. IID may attach as a hardship-license condition under §24(1)(c)(1) when the driver's chemical-test BAC at arrest was 0.15 or greater (registrar discretion), or as a condition of a §24D Cahill / second-chance hardship grant for a second-offense defendant whose prior is 10+ years old (mandatory, hardship period plus 2 years). These are off-tier conditions, not categorical first-offense IID. - Second offense: IID is mandatory under §24½. A second-offense conviction triggers categorical IID for the duration of any conditional hardship-license period and for an additional 2 years following full-license reinstatement. The minimum IID period for multiple OUI offenders is 2 years. - Third or subsequent offense: IID is mandatory under §24½. Same framework as second offense — IID for the full hardship-license period plus 2 years following reinstatement. Third-and-fourth-offense defendants face longer underlying revocation periods (8 / 10 years) so the practical IID exposure stretches across the full revocation-plus-IID window. Fifth-and-subsequent-offense defendants face lifetime revocation with no hardship — IID does not arise because operating privileges are not restored. IID duration tracks the underlying license-action duration cited in ma-faq-8. Devices must be RMV-certified; installation and monthly monitoring fees are paid by the offender.