Legal cannabis in Massachusetts comes with one rule that never bends: you can't drive under the influence of it. Driving high is treated as operating under the influence (OUI), under the same statute that covers drunk driving, and the penalties are the same. This guide explains what the law says about driving high in Massachusetts, what a first offense can cost, how open-container rules work for cannabis in a car, and how to plan so the question never comes up. It's for adults 21 and over, and it isn't legal advice.
Key takeaways
- Driving high is OUI. M.G.L. c. 90, § 24 covers operating under the influence of marijuana, not just alcohol.
- No THC number. The 0.08% limit is for blood alcohol. Marijuana cases turn on evidence of impairment.
- First offense: a fine of $500 to $5,000, up to 2½ years in jail, and a one-year license suspension on conviction, per the RMV.
- Sealed or stowed. An open container in the passenger area can mean a civil penalty of up to $500.
- Plan the ride before you consume. Delivery brings the order to you, so nobody has to drive to pick it up.
The law: marijuana OUI is OUI
Massachusetts didn't write a separate cannabis driving law. The existing OUI statute, M.G.L. c. 90, § 24, already makes it a crime to operate a motor vehicle on a public way while under the influence of "marijuana, narcotic drugs, depressants or stimulant substances," alongside alcohol.
The cannabis law says so explicitly. Chapter 94G, § 2 says the cannabis law doesn't amend existing penalties for operating, navigating or being in actual physical control of any motor vehicle, train, aircraft, motorboat or other motorized form of transport or machinery while impaired by marijuana. So "it's legal now" doesn't reach the driver's seat, the helm of a boat or the controls of machinery at work.
Every Massachusetts cannabis label carries the same reminder. It's part of the required warning: "It is against the law to drive or operate machinery when under the influence of this product." The Cannabis Control Commission (CCC) puts it more simply on its Know the Laws page: it's illegal to drive while under the influence of cannabis.
Is there a legal THC limit?
No. This is the biggest difference from alcohol. For alcohol, c. 90, § 24 sets a per se limit of 0.08% blood alcohol. There's no equivalent THC number in the statute. That means:
- There's no "safe" amount you can point to. A case can be built on how you were driving and how you appeared, not on a lab result crossing a line.
- Feeling fine isn't a defense. Impairment is judged by evidence, and what you think of your own driving isn't part of it.
- Edibles deserve extra caution. The state-required warning on edibles says their impairment effects may be delayed by two hours or more. Someone who eats an edible and drives before it's taken effect can end up impaired partway through the drive.
How roadside evidence can be used in marijuana cases has been litigated. The state's highest court addressed roadside assessments in Commonwealth v. Gerhardt (2017), and the court system's law library publishes the model jury instruction from that decision. The practical point for drivers is simple: don't put yourself in a position where any of it matters.
What a first offense can cost
Penalties under c. 90, § 24 escalate with each prior offense. For a first offense, the statute provides:
- A fine of $500 to $5,000
- Imprisonment of up to two and a half years
- License consequences handled by the Registry of Motor Vehicles
The RMV's published table for drivers over 21 lists a one-year suspension after a first-offense OUI conviction for alcohol or drugs. A first offender may instead be assigned to a driver education program as a condition of probation under c. 90, § 24D, and in that case the RMV lists a suspension of 45 to 90 days. Second and later offenses bring longer suspensions (two years, eight years, ten years, then lifetime) and an ignition interlock requirement.
Refusing a chemical test
Massachusetts is an implied-consent state. According to the RMV, if you're arrested for OUI and refuse a chemical test, your license is suspended immediately, and the refusal suspension for a driver over 21 with no prior OUIs is 180 days. It's an administrative penalty rather than a crime, and it runs separately from any suspension that follows a conviction.
Add the indirect costs (insurance, legal fees, time without a license) and one bad decision can take years to unwind.
Cannabis in the car: open-container rules
Carrying cannabis in a car isn't illegal. Carrying it open in the passenger area is. Under c. 94G, § 13, you can't possess an open container of marijuana or marijuana products in the passenger area of a motor vehicle on a public way. The civil penalty is up to $500.
- "Open" means the seal is broken or some of the contents are gone.
- The passenger area is the seating area and anything within reach of it. It doesn't include the trunk or a locked glove compartment.
- It applies to everyone in the car, not just the driver.
The easy habit: keep delivery orders in their original sealed, child-resistant packaging, and put anything that's been opened in the trunk. The where you can consume cannabis guide covers the related public-use rules.
Passengers and parked cars
Consuming in a car isn't a loophole. A car on a public road or in a public lot isn't a private place, and an open container in the passenger area is already a violation. A driver sitting next to a passenger who's consuming is also inviting an OUI investigation. Wait until you're home.
Crossing state lines
Massachusetts law stops at the border. The CCC is direct about it: it's illegal to drive across state lines with cannabis, or to take it outside Massachusetts by plane, train, boat or any other mode of transportation. That includes trips to New Hampshire, Rhode Island and Maine, even though some of those states have their own legal markets.
How to plan so you never have to think about this
- Decide how you're getting home before you consume. A rideshare, a taxi, public transit, a friend who isn't using, or staying put.
- Have it delivered instead of driving to get it. Licensed delivery brings the order to your door, and nobody in the house has to drive to a store. Our how cannabis delivery works guide explains the process.
- Time it around your plans. If you'll need to drive later, don't consume first. With edibles, remember the onset caution (impairment effects may be delayed by two hours or more): start low, go slow, and keep the rest of the evening car-free. The edibles guide for first-timers explains why timing is tricky.
- Don't add alcohol to the plan. The same OUI statute covers both, and either one is enough for a charge.
- Keep product sealed in transit. If you're bringing something to a friend's place, keep it sealed and in the trunk. The gifting guide covers what you're allowed to share.
Why delivery fits a no-driving plan
Delivery doesn't make any product safer to drive on, but it removes one reason to get in the car. You order online, pick a window, and the order comes to your home, where you meet the driver with your pre-verified ID. Our current windows are 12–2pm, 2–4pm, 4–6pm, 6–8pm, 8–10pm and 10–11pm Monday to Saturday; 12–2pm through 8–10pm on Sunday, and same-day orders need to be in by 9pm (7pm on Sundays).
We deliver across Boston neighborhoods such as Dorchester and Jamaica Plain, and in towns like Quincy, Waltham and Framingham. The delivery areas page lists every town we serve. Every product page shows its state-tracked lab results. The lab results page explains what each field means.
Browse the menu and let the car stay parked. Adults 21+ only.
This guide summarizes Massachusetts law as of September 2026 and isn't legal advice. If you're facing a charge, talk to a Massachusetts attorney. For adults 21+ only.
Frequently asked questions
Is it illegal to drive high in Massachusetts?
Yes. M.G.L. c. 90, § 24 makes it a crime to operate a motor vehicle while under the influence of marijuana, the same statute that covers alcohol. Legal adult-use cannabis didn't change that: c. 94G, § 2 says the cannabis law doesn't amend existing penalties for operating while impaired.
Is there a legal THC limit for driving in Massachusetts, like 0.08% for alcohol?
No. The 0.08% figure in c. 90, § 24 applies to blood alcohol. The statute doesn't set a numeric THC threshold, so marijuana OUI cases turn on evidence of impairment rather than a number.
What's the penalty for a first marijuana OUI in Massachusetts?
Under c. 90, § 24, a first offense carries a fine of $500 to $5,000 and up to two and a half years in jail. The RMV's published table lists a one-year license suspension after a first-offense conviction, or 45 to 90 days if the court assigns you to a first-offender program under c. 90, § 24D.
Can I keep cannabis in my car in Massachusetts?
Yes, if it's sealed or stored outside the passenger area. An open container (a broken seal or partly used contents) in the passenger area can bring a civil penalty of up to $500. The trunk or a locked glove compartment is the safe place.
Can a passenger consume cannabis in a moving car?
No. The open-container rule covers the whole passenger area, not just the driver, and consuming in a car on a public road is a quick way to invite an OUI investigation for the driver.
Sources
- M.G.L. c. 90, § 24: Driving under the influence of intoxicating liquor or drugs (malegislature.gov) · malegislature.gov
- M.G.L. c. 94G, § 2: Limitations of chapter (malegislature.gov) · malegislature.gov
- M.G.L. c. 94G, § 13: Open containers, public consumption and furnishing to minors (malegislature.gov) · malegislature.gov
- Alcohol and drug suspensions for over 21 years of age (Mass. Registry of Motor Vehicles, mass.gov) · mass.gov
- Massachusetts law about drunk or drugged driving (Trial Court Law Libraries, mass.gov) · mass.gov
- Know the Laws (Cannabis Control Commission) · masscannabiscontrol.com
Rules change. We check official sources when we update a post; confirm current requirements with the Cannabis Control Commission before relying on them.