What auto insurance does and why states require it

Auto insurance is a contract between you and an insurance company: you pay a premium, and the company agrees to pay for certain losses if you cause an accident or your vehicle is damaged. Liability coverage — the part that pays for injuries or property damage you cause to someone else — is required by law in every state. The minimum amounts vary by state, but most require at least $25,000 in bodily injury coverage per person and $50,000 per accident, plus $25,000 in property damage coverage.

The other types of coverage — collision, comprehensive, uninsured motorist, medical payments — are optional in most states, though your lender will require collision and comprehensive if you have a loan or lease on the vehicle. Understanding what each type covers and what it costs helps you decide which combination makes sense for your situation and your vehicle's value.

Key Takeaways

  • Liability coverage is required by law in every state and pays for injuries or damage you cause to someone else, not damage to your own vehicle.
  • Collision and comprehensive coverage protect your own vehicle but are optional unless you have a loan or lease, in which case your lender requires them.
  • Deductibles — the amount you pay out of pocket before insurance kicks in — directly affect your premium; higher deductibles mean lower monthly costs.
  • Insurance companies use driving history, age, vehicle type, and location to set your rate, and these factors vary significantly between insurers.
  • Discounts for bundling home and auto policies, maintaining a clean driving record, or completing a defensive driving course can lower your premium by 10 to 25 percent.

Liability coverage: what it covers and what it does not

Liability coverage has two parts. Bodily injury liability pays medical bills, lost wages, and pain-and-suffering damages if you injure someone in an accident you cause. Property damage liability pays to repair or replace the other person's vehicle or other property — a fence, mailbox, or building — that you damage. If you cause a serious accident, these costs can easily exceed $100,000, which is why many people carry limits higher than the state minimum.

Liability coverage does not pay for damage to your own vehicle, your own medical bills, or injuries to you or your passengers. It also does not cover accidents you cause while driving for commercial purposes — for example, if you use your personal vehicle for rideshare or delivery work, you need commercial auto insurance on top of your personal policy. If you cause an accident and your liability limit is too low to cover the damages, you can be sued personally for the difference.

Collision and comprehensive: protecting your own vehicle

Collision coverage pays to repair or replace your vehicle if you hit another car, a tree, a guardrail, or any other object — whether the accident is your fault or not. Comprehensive coverage pays for damage from events you cannot control: theft, vandalism, weather (hail, flooding, wind), hitting an animal, or glass damage. Together, these two cover most ways your vehicle can be damaged.

Both collision and comprehensive require you to pay a deductible — typically $250, $500, or $1,000 — out of your own pocket before the insurance company pays the rest. If your vehicle is worth $5,000 and you cause $3,000 in collision damage with a $500 deductible, the insurance company pays $2,500 and you pay $500. If your vehicle is worth $2,000 and the damage is $3,000, the insurance company pays the full $2,000 (the vehicle's value) minus your deductible, and the vehicle is declared a total loss.

Uninsured and underinsured motorist coverage

Uninsured motorist coverage protects you if you are hit by a driver who has no insurance or leaves the scene. Underinsured motorist coverage protects you if the other driver's liability limit is too low to cover your damages. Both cover your medical bills, lost wages, and pain and suffering — the same things the other driver's liability insurance would cover if they had adequate coverage.

These coverages are required in some states and optional in others, but they are inexpensive (usually $10 to $30 per month) and protect you against a real risk: roughly one in eight drivers nationwide is uninsured, and that number is higher in some states and regions. If you are hit by an uninsured driver and you do not have this coverage, you have to sue the driver personally to recover damages, which is often unsuccessful because they have no assets.

Medical payments and personal injury protection

Medical payments coverage pays your medical bills and your passengers' medical bills after an accident, regardless of who caused it. It covers hospital visits, surgery, dental work, and ambulance fees. Personal injury protection (PIP), available in some states, is similar but also covers lost wages and other expenses like childcare or household help while you recover.

These coverages are optional in most states and typically cost $10 to $25 per month. They are useful if you do not have good health insurance or if you have a high deductible on your health plan, because they pay medical bills quickly without requiring you to prove fault. If you have comprehensive health insurance, the benefit is smaller, though some people still carry it to avoid using their health insurance deductible.

How insurance companies set your rate

Insurance companies use several factors to calculate your premium. Driving history is the largest factor: accidents, traffic violations, and claims you have filed all increase your rate. Age and gender matter because younger drivers and male drivers have higher accident rates. Vehicle type affects cost because some vehicles are more expensive to repair, more likely to be stolen, or have higher injury rates in crashes. Location affects cost because some areas have more accidents, theft, or uninsured drivers.

Other factors include your credit score (in most states), annual mileage, whether you use the vehicle for commuting, and how long you have been insured. The weight given to each factor varies by company and by state. Two insurers may quote you very different rates for the same coverage because they weigh these factors differently or use different accident data. This is why shopping around — getting quotes from at least three insurers — usually saves money.

Deductibles, limits, and how they affect your premium

Raising your deductible from $250 to $1,000 typically lowers your collision and comprehensive premium by 15 to 30 percent, because you are agreeing to pay more out of pocket if you have a claim. Raising your liability limit from the state minimum to $100,000 or $250,000 typically costs $10 to $30 more per month, depending on your driving history and location. The higher limit protects you against a lawsuit if you cause a serious accident.

The right deductible depends on how much you can afford to pay out of pocket. If you have $1,000 in savings, a $1,000 deductible is risky because one accident could wipe out your emergency fund. If you have $10,000 in savings, a $1,000 deductible makes sense because it saves you money on premiums. The right liability limit depends on your assets and risk tolerance; if you own a home or have significant savings, a limit of at least $100,000 is common.

Discounts and ways to lower your premium

Most insurance companies offer discounts that can lower your premium by 10 to 25 percent. Multi-policy discounts (bundling auto and home insurance) typically save 15 to 25 percent. Safe driver discounts reward three to five years without accidents or violations. Defensive driving course discounts explore if you complete an approved course, usually saving 5 to 10 percent for three years. Low-mileage discounts explore if you drive fewer than 7,500 or 10,000 miles per year.

Some companies offer discounts for paying in full rather than monthly, for setting up automatic payments, or for maintaining continuous coverage without lapses. A few offer usage-based discounts if you install a mobile app or device that monitors your driving habits. Ask your insurer which discounts you may be may be able to access for, and recalculate your premium after any major life change — moving, retiring, or paying off a car loan — because your rate may drop.

Frequently Asked Questions

What happens if I drive without insurance?

Driving without insurance is illegal in every state. Penalties include fines ($500 to $2,000 or more), license suspension, and in some states jail time. If you cause an accident while uninsured, you are personally liable for all damages, and the other driver can sue you for medical bills, vehicle repairs, and pain and suffering. You can also be required to carry an SR-22 form (proof of insurance) for three years, which costs extra.

Does my insurance cover me if someone else drives my car?

Yes, in most cases. Your insurance follows the vehicle, not the driver, so if a friend or family member borrows your car and causes an accident, your insurance typically pays. However, if you regularly let someone else drive your car, you should add them to your policy so they are covered under all circumstances. If you lend your car to someone you know has a poor driving record, your insurer may deny the claim.

What is a grace period if I miss a payment?

Most insurance companies give you a grace period of 10 to 30 days after your payment is due before they cancel your policy. During this time you are still covered. If you do not pay by the end of the grace period, your policy lapses and you are driving uninsured. If you miss a payment, contact your insurer when ready to make arrangements; many will work with you if you communicate before the grace period ends.

Can I change my coverage or deductible mid-policy?

Yes. You can usually change your coverage, deductible, or limits at any time, and the change takes effect when ready or on a date you choose. If you raise your deductible, your premium may be refunded for the remainder of your policy term. If you lower your deductible or add coverage, you will pay the difference. Changes do not require you to start a new policy.

What should I do when ready after an accident?

Call the police if anyone is injured or there is significant damage. Exchange name, phone number, address, insurance company, and policy number with the other driver. Take photos of the damage, the accident scene, and the other vehicle's license plate. Get contact information from any witnesses. Then call your insurance company to report the accident. Do not admit fault or sign anything except police reports and insurance documents.