Uninsured & underinsured motorist
Uninsured and underinsured motorist coverage protects you when the at-fault driver can't cover the damage they caused. Here's what it covers and why it matters more than people expect.
Uninsured motorist (UM) and underinsured motorist (UIM) coverage pay for your injuries and, in some cases, your vehicle's damage when the at-fault driver either has no insurance or doesn't carry enough to cover what they caused. It's the mirror image of liability: liability pays other people when you're at fault; UM/UIM pays you when someone else is at fault and can't make you whole.
How UM and UIM differ
Uninsured motorist coverage applies when the at-fault driver has no auto insurance at all, or in a hit-and-run where the driver is never identified. Underinsured motorist coverage applies when the at-fault driver has insurance, but their liability limits aren't enough to cover your medical bills and losses. Both cover injuries to you and your passengers, and in some states they also cover damage to your vehicle.
Massachusetts rules
Massachusetts requires all auto policies to include a minimum of $20,000 per person and $40,000 per accident in uninsured motorist coverage. Underinsured motorist coverage is optional in Massachusetts and must be purchased separately — many drivers skip it without realizing what it does, or assume UM covers both scenarios. It doesn't.
Why the limit matters
A meaningful share of drivers on the road carry state-minimum liability or no insurance at all. If one of them causes a serious injury accident, their limits can be exhausted quickly — and without UM/UIM at a matching level, you're left with the shortfall. Most agents recommend carrying UM and UIM limits equal to your own liability limits. The added premium is typically small because these claims are less frequent than at-fault claims, but the protection matches what you'd want available if the roles were reversed.