Auto Insurance

Auto insurance is a contract in which an insurer agrees, in exchange for a premium, to pay for specified losses arising from the ownership or use of a vehicle. What makes it unusual among consumer policies is that it is really several policies stapled together: a liability section that pays third parties for harm you cause, physical damage sections that pay for your own vehicle, and one or more first-party medical and uninsured-motorist sections that pay you and your passengers. Each has its own limit, its own deductible or lack of one, and its own set of triggering events, and a shopper comparing two quotes is usually comparing different bundles rather than different prices for the same thing. All but one state requires liability coverage of some kind: 49 states and the District of Columbia mandate it, and New Hampshire is the sole exception. What the mandate reaches varies, and one state requires property damage liability without requiring bodily injury liability at all.

Liability is split into bodily injury and property damage, and it is the coverage whose failure is unbounded. A damaged car costs the value of a car; a serious at-fault injury can cost more than the car, the house and the retirement accounts together, because the bill is someone else's medical care, rehabilitation and lost earnings. State minimums are a floor and insurance regulators say so directly: the state-required minimum coverages are usually not enough to fully protect you and your assets. Among states that require bodily injury liability at all, the minimums run up to $50,000 per person and $100,000 per accident with $25,000 of property damage, and the claim that many were set decades ago is literally citable: California's 15/30/5 limits stood from 1967 until January 1, 2025, fifty-six years, before being raised to 30/60/15. Note the floor is lower than "lowest minimum" suggests, because in Florida there is no bodily injury liability requirement for an ordinary driver at all: the state's own motor vehicle agency puts the requirement at $10,000 of personal injury protection and $10,000 of property damage liability, and its $10,000/$20,000/$10,000 figures are a financial-responsibility standard that attaches in defined circumstances rather than a coverage every driver must carry. Where a judgment exceeds the limit, the remainder reaches personal assets and, in many states, future wages: four states fully exempt wages from garnishment for a private money judgment, and the rest permit it subject to the federal cap.

Collision and comprehensive cover your own vehicle, and the dividing line is not where readers guess. Collision responds to a crash. Comprehensive responds to most of the rest, and hitting an animal falls under comprehensive rather than collision, as does flood damage to the vehicle, so carrying collision without comprehensive leaves a deer strike and a flooded car uncovered. Both carry a deductible, and it applies per occurrence, which means a household with two unrelated claims in the same year pays it twice. The decision to drop them is a question about the specific car's value and replaceability rather than a rule about age or mileage.

Uninsured and underinsured motorist coverage is the one most drivers do not know they need, and the numbers explain why. In 2023, 15.4% of motorists carried no insurance at all, ranging from 5.7% in Maine to 28.2% in Mississippi, and a further 18.0% were underinsured. Between the two, roughly a third of the drivers on the road cannot fully pay for the harm they cause. Without this coverage, being hit by one of them leaves your own injuries as your own problem.

Personal injury protection and medical payments are where the most persistent misconception lives. The tidy version, that PIP belongs to no-fault states and medical payments coverage to everywhere else, is false in both directions. PIP is compulsory in eighteen states and optional in six, which is more states than operate a no-fault system: nine states plus Puerto Rico have mandatory no-fault and three offer a choice, twelve in total, while eleven further "add-on" states are ordinary tort systems that nonetheless require or permit PIP. No state has adopted no-fault since 1990 and five have repealed it. So the only reliable statement is that PIP may well be required or available where you live regardless of the liability system, and how much it matters depends on how good your health insurance already is.

Two coverages are worth naming because they are commonly mispriced by buyers. Gap coverage pays the difference between the loan or lease balance and what the car was worth when it was totaled, which is a real exposure on a long loan with a small down payment and a pointless expense once there is equity in the vehicle. Rental reimbursement and roadside assistance are inexpensive additions that pay small, predictable, absorbable costs, which is the category of risk a household is generally better placed to carry itself.

One boundary connects this policy to the rest of a household's coverage. Home and auto liability cover disjoint sets of events, since a homeowners policy responds to non-auto accidents, which is why the two limits do not reinforce each other and why the lower of the two is the one that governs a household's exposure. An umbrella policy sits above both, and insurers commonly require the underlying auto and homeowners liability limits to be raised to a stated level before they will write one.

A policy lists the covered vehicles, the drivers, and each coverage with its own limit and deductible. After a loss, the coverage that responds is decided by what happened rather than by what the policy cost: a claim against you goes to liability, damage to your own car goes to collision or comprehensive, and your own injuries go to PIP, medical payments or uninsured motorist coverage depending on the state and the other driver. Liability claims carry no deductible; physical damage claims do. Whether a friend who borrows the car is covered is decided by the policy's own definition of who counts as an insured, which is worth reading before lending it rather than afterwards.

A hypothetical example of how the per-occurrence deductible actually works. Suppose a policy carries a $1,000 deductible on both collision and comprehensive. In March a hailstorm causes $4,200 of damage, a comprehensive claim, and the insurer pays $3,200. In September the same car is damaged in a $6,500 collision, and the insurer pays $5,500. The household has paid $1,000 twice, for $2,000 out of pocket in one year, because the deductible attaches to each occurrence rather than resetting annually the way a health plan deductible does. That is also the arithmetic behind raising a deductible: it lowers the premium every year and costs more only in the years a claim happens.

The one saving available in this market that costs no protection is re-shopping the same limits. Prices for identical coverage differ substantially between insurers, so comparing the same limits and deductibles across carriers every few years is worth more than trimming coverage. Where liability limits are the thing being compared, raising them is generally the cheapest part of the policy to improve, because the largest share of most premiums is coverage on the vehicle rather than coverage for the people it might hurt.

Pros

• Liability coverage transfers an unbounded risk to an insurer for a modest and predictable premium.
• Raising liability limits is usually inexpensive relative to the exposure it covers.
• Comprehensive and collision make an otherwise unaffordable total loss absorbable while the car is worth enough to matter.
• Uninsured motorist coverage addresses a risk that roughly a third of drivers on the road create.

Cons

• "Full coverage" is a phrase that tells a buyer nothing about their limits, and it is frequently mistaken for adequacy.
• State minimum limits are far below the cost of a single serious injury, and buying them is the most common way to be badly insured while legally compliant.
• Deductibles apply per occurrence, so a bad year costs more than the deductible suggests.
• Physical damage coverage on an old car can cost more in premium than the insurer would ever pay out.
• Small add-ons such as rental reimbursement pay for losses a household could absorb, at a margin the seller keeps.