Every state sets a minimum amount of liability insurance a driver must carry, and many drivers treat that number as the correct amount. It was never designed to be sufficient.
What the minimum actually is
State minimums are a legislative floor, chosen to keep uninsured drivers off the road while keeping coverage affordable enough that most people can comply. Adequacy is not the design goal.
The limits are typically expressed as three numbers: bodily injury per person, bodily injury per accident, and property damage. Each is a separate ceiling that applies independently.
Many of these figures were set decades ago and revised rarely, which means their real value has eroded steadily against medical and repair costs while the statutory number stayed the same.
The property damage limit is the first to fail
Property damage limits are usually the smallest of the three, and modern vehicles are expensive to repair or replace. A single collision with a late-model truck can exceed the limit outright.
Sensors in bumpers, cameras in mirrors and aluminum body panels have all raised repair costs well above what a comparable repair would have run a generation ago.
When the limit is exhausted the shortfall does not disappear. It becomes a claim against the at-fault driver personally, which is the exposure the coverage was supposed to prevent.
Bodily injury claims escalate quickly
Medical costs stack in layers: emergency transport, imaging, surgery, hospital stay, rehabilitation and lost income. A crash with lasting injury moves past a low per-person limit early in that sequence.
The per-accident limit compounds the problem, because it caps the total paid across everyone injured. A vehicle with several occupants can consume the whole amount among them.
Once the policy pays its limit, the insurer's defense obligation typically ends as well, and the driver is left arranging their own representation for anything remaining.
Uninsured motorists are a separate gap
Liability coverage pays for damage a driver causes to others. It does nothing when the other driver is at fault and carries no insurance, or carries only a minimum policy.
Uninsured and underinsured motorist coverage exists to fill that gap, and its importance rises in states where a large share of drivers carry nothing at all.
Because it steps in exactly where the other party's policy stops, its useful limit is generally matched to a driver's own liability limits rather than set independently.
Why raising limits costs less than expected
The bulk of an insurer's payouts are small and moderate claims, which happen at every coverage level. Large claims are rare, so insuring against them adds comparatively little to a premium.
That pricing structure means moving from minimum limits to substantially higher ones usually costs far less per unit of coverage than the first dollars of the policy did.
Drivers with assets to protect are the ones for whom the difference matters most, and an agent or broker can explain how the numbers apply in a specific state.