Uninsured motorist coverage rules in Massachusetts

You did everything right, and the other driver had no insurance, handed you a fake policy number, or drove off before you could read the plate. In Massachusetts the coverage that steps in is your own uninsured motorist protection, and it is not optional. Every auto policy issued in the Commonwealth has to include it.

This page sticks to what Massachusetts law requires and how a claim works here. The national hub covers the general idea of uninsured motorist coverage; below are the Massachusetts numbers, deadlines, and quirks.

Uninsured motorist coverage is required, and the minimum went up in 2025

Massachusetts is one of a small group of states that makes uninsured motorist (UM) coverage compulsory. Under M.G.L. c. 175, section 113L, no auto policy can be issued or renewed on a vehicle registered here unless it provides UM coverage at the same limits the policy carries for bodily injury to others.¹ In the standard Massachusetts Automobile Insurance Policy this is Part 3, "Bodily Injury Caused by an Uninsured Auto."²

Because UM tracks your bodily-injury limit, the 2025 increase to the state minimums raised the UM floor with it. For policies issued or renewed on or after July 1, 2025, the compulsory limits are 25,000 dollars per person and 50,000 per accident for bodily injury, plus 30,000 for property damage, often written as 25/50/30.³⁴ Those were the first increases since 1988. If you carry only the state minimum, your UM coverage sits at 25/50 too.

UM pays in a few situations: when the at-fault driver has no bodily-injury liability insurance, when that driver's policy has lapsed, and in hit-and-run or "unidentified auto" cases where you never learn who hit you.¹² The catch is fault. UM only pays if you are "legally entitled to recover" from the other driver, which means that driver has to be the one who caused the crash.¹ Massachusetts follows a modified comparative negligence rule, so if you are found more than 50 percent at fault you recover nothing, and a smaller share of fault reduces what you collect.⁵

Underinsured coverage is a separate, optional purchase

Here is the part that surprises people. Underinsured motorist (UIM) coverage, which fills the gap when the at-fault driver has some insurance but not enough, is not automatic in Massachusetts. Section 113L requires insurers to offer it and to notify you that you may buy it, but you can turn it down, and the standard policy treats it as the optional Part 12.¹²

That gap matters more now than it used to. With so many drivers carrying the new 25/50 minimum, a serious injury can blow past the at-fault driver's limit fast. Without UIM of your own, that shortfall is yours to absorb. Buying UIM at a limit well above 25/50 is one of the most useful things a Massachusetts driver can do to guard against a badly underinsured driver.

How a Massachusetts UIM claim actually pays out

A UIM claim here is not a simple top-up. Two rules from Part 12 of the standard policy shape it.

First, exhaustion. You generally have to recover the full bodily-injury limit from the at-fault driver's insurer before your own UIM applies.² Second, offset. Your UIM insurer subtracts whatever you already received from the at-fault driver. If your UIM limit is 100,000 dollars and you collected the other driver's 25,000, the most your UIM can add is 75,000.²

There is a procedural trap sitting between those two steps. Before you sign any settlement with the at-fault driver, you have to get your UIM insurer's written consent. The standard policy bars you from settling or releasing the at-fault driver without it, though the insurer is not supposed to withhold consent unreasonably.² Settle without asking, and you can forfeit your own UIM claim. Get the consent in writing first.

Disputes usually go to arbitration

If you and your own insurer cannot agree on what your UM or UIM claim is worth, the standard policy sends the disagreement to arbitration rather than a jury, as long as the amount in dispute stays within the policy limits. When the claim exceeds those limits, either side can take it to court.² The same setup applies to both Part 3 uninsured claims and Part 12 underinsured claims.

No stacking, and the household rule

Massachusetts flatly bars stacking. Under section 113L you cannot add together the UM limits of two or more vehicles or two or more policies to build a larger pool.¹ If you are hurt and you are not a named insured on any UM policy, you can reach the policy of a resident relative that carries the highest UM limit, whether or not that particular car was in the crash. When two such policies share the same limit, they contribute pro rata.¹

The deadlines and thresholds that still apply

Personal Injury Protection comes first. Massachusetts is a no-fault state, so your own PIP pays up to 8,000 dollars for medical bills and related losses like a portion of lost wages, regardless of who caused the crash, including in an uninsured-driver case.⁶ Once a treating physician sends notice, the insurer has to start paying within ten days or send written notice that it is refusing.⁶ Present your PIP claim as soon as practicable, and within two years of the crash at the outside.⁶

To recover for pain and suffering on top of PIP, you have to clear the tort threshold in M.G.L. c. 231, section 6D. Reasonable medical expenses have to exceed 2,000 dollars, unless the injury caused death, a fracture, loss of a body member, permanent and serious disfigurement, or substantial loss of sight or hearing.⁷ That threshold applies to the injury side of a UM or UIM claim too.

Then there is the clock. Massachusetts gives you three years from the date of the crash to bring a personal-injury claim under M.G.L. c. 260, section 2A.⁸ A UM or UIM claim runs on its own contract-based timeline, and the policy can require prompt notice, so tell your insurer early rather than sitting on it.

What to do after an uninsured or hit-and-run crash

Call the police and make sure a report gets written, especially in a hit-and-run, where the official crash report is often the only proof that the other vehicle existed. You can obtain that report from the Massachusetts RMV Crash Records Unit.⁹ For the details and current Massachusetts crash figures, see our Massachusetts crash reports page.

Notify your own insurer quickly, since UM and UIM are first-party claims against your carrier. If an uninsured driver damaged your car, that is a property claim separate from the bodily-injury UM coverage, and any lost resale value is worth checking on our Massachusetts diminished value page. Because these claims turn on fault, offsets, consent, and arbitration, they reward careful handling. If you want representation, start with our Massachusetts legal directory.

This is general information, not legal advice.

Sources

1. Mass. Gen. Laws ch. 175, section 113L. https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXXII/Chapter175/Section113L

2. Massachusetts Automobile Insurance Policy, standard form (2024 edition), Part 3 and Part 12. https://www.safetyinsurance.com/doclib/mass_auto/forms/2024_policy_jacket.pdf

3. Acts of 2024, c. 275 (amending M.G.L. c. 90, section 34A). https://malegislature.gov/Laws/SessionLaws/Acts/2024/Chapter275

4. Massachusetts, 2025 New Motor Vehicle Mandatory Coverage Limits. https://www.mass.gov/doc/2025-a-new-motor-vehicle-mandatory-coverage-limits/download

5. Mass. Gen. Laws ch. 231, section 85. https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section85

6. Mass. Gen. Laws ch. 90, section 34M. https://malegislature.gov/Laws/GeneralLaws/PartI/TitleXIV/Chapter90/Section34M

7. Mass. Gen. Laws ch. 231, section 6D. https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleII/Chapter231/Section6D

8. Mass. Gen. Laws ch. 260, section 2A. https://malegislature.gov/Laws/GeneralLaws/PartIII/TitleV/Chapter260/Section2A

9. Massachusetts RMV, Request a Copy of a Police Crash Report. https://www.mass.gov/how-to/request-a-copy-of-a-police-crash-report