Automobile insurance is insurance purchased for cars, trucks, and other vehicles. Its primary use is to provide protection against losses incurred as a result of traffic accidents and against liability that could be incurred in an accident.

Public policy

In many jurisdictions it is compulsory to have vehicle insurance before using or keeping a motor vehicle on public roads. Most jurisdictions relate insurance to both the car and the driver, however the degree of each varies greatly.

United Kingdom

In 1930, the UK government introduced a law that required every person who used a vehicle on the road to have at least third party personal injury insurance.

Today UK law is defined by the The Road Traffic Act 1988, which was last modified in 1991. The act requires that some motorists either be insured, have a security, or have made a specified deposit (£500,000 as of 1991) with the Accountant General of the Supreme Court, against their liability for injuries to others (including passengers) and for damage to other persons' property resulting from use of a vehicle on a public road or in other public places.

Insurance which satisfies the requirement of the act, for those who require cover, is called third party insurance. It is an offence to drive your car, or allow others to drive it, without at least third party insurance whilst on the public highway (or public place Section 143(1)(a) RTA 1988 as amended 1991); however, no such legislation applies on private land.

Vehicles which are exempted by the act, from the requirement to be covered, include those owned by certain: councils and local authorities, national park authorities, education authorities, police authorities, fire authorities, heath service bodies and security services.

The insurance certificate or cover note issued by the insurance company constitutes legal evidence that the vehicle specified on the document is indeed insured. The law says that an authorized person, such as the police, may require a driver to produce an insurance certificate for inspection. If the driver cannot show the document immediately on request, then the driver will usually be issued a HORT/1 with seven days, as of midnight of the date of issue, to take a valid insurance certificate (and usually other driving documents as well) to a police station of the driver's choice. Failure to produce an insurance certificate is an offence.

Insurance is more expensive in Northern Ireland than in other parts of the UK.

Most motorists in the UK are required to prominently display a vehicle licence (tax disc) on their vehicle when it is kept or driven on public roads. This helps to ensure that most people have adequate insurance on their vehicles because you are required to produce an insurance certificate when you purchase the disc. However it is a known practice for some people to purchase insurance to gain the certificate and then to cancel the insurance and gain a full refund within the statutory 14 day cooling off period.

The Motor Insurers Bureau compensates the victims of road accidents caused by uninsured and untraced motorists. It also operates the Motor Insurance Database, which contains details of every insured vehicle in the country.

United States

In the United States, auto insurance is compulsory in most states, though enforcement of the requirement varies from state to state. The state of New Hampshire, for example, does not require motorists to carry liability insurance, while in Virginia residents must pay the state a $500 annual fee per vehicle if they choose not to buy liability insurance.[4] Penalties for not purchasing auto insurance vary by state, but often involve a substantial fine, license and/or registration suspension or revocation, as well as possible jail time in some states. Usually, the minimum required by law is third party insurance to protect third parties against the financial consequences of loss, damage or injury caused by a vehicle.

Basis of premium charges

Depending on the jurisdiction, the insurance premium can be either mandated by the government or determined by the insurance company in accordance to a framework of regulations set by the government. Often, the insurer will have more freedom to set the price on physical damage coverages than on mandatory liability coverages.

When the premium is not mandated by the government, it is usually derived from the calculations of an actuary based on statistical data. The premium can vary depending on many factors that are believed to have an impact on the expected cost of future claims. Those factors can include the car characteristics, the coverage selected (deductible, limit, covered perils), the profile of the driver (age, gender, driving history) and the usage of the car (commute to work or not, predicted annual distance driven).

Gender

Men average more miles driven per year than women do, and have a proportionally higher accident involvement at all ages. Insurance companies cite women's lower accident involvement in keeping the youth surcharge lower for young women drivers than for their male counterparts, but adult rates are generally unisex. Reference to the lower rate for young women as "the women's discount" has caused confusion that was evident in news reports on a recently defeated EC proposal to make it illegal to consider gender in assessing insurance premiums.Ending the discount would have made no difference to most women's premiums.

Age

Teenage drivers who have no driving record will have higher car insurance premiums. However young drivers are often offered discounts if they undertake further driver training on recognised courses, such as the Pass Plus scheme in the UK. In the U.S. many insurers offer a good grade discount to students with a good academic record and resident student discounts to those who live away from home. Generally insurance premiums tend to become lower at the age of 25. Senior drivers are often eligible for retirement discounts reflecting lower average miles driven by this age group.

Distance

Some car insurance plans do not differentiate in regard to how much the car is used. However, methods of differentiation would include:

Reasonable estimation

Several car insurance plans rely on a reasonable estimation of the average annual distance expected to be driven which is provided by the insured. This discount benefits drivers who drive their cars infrequently but has no actuarial value since it is unverified.

Odometer-based systems

Cents Per Mile Now(1986) advocates classified odometer-mile rates. After the company's risk factors have been applied and the customer has accepted the per-mile rate offered, customers buy prepaid miles of insurance protection as needed, like buying gallons of gasoline. Insurance automatically ends when the odometer limit (recorded on the car’s insurance ID card) is reached unless more miles are bought. Customers keep track of miles on their own odometer to know when to buy more. The company does no after-the-fact billing of the customer, and the customer doesn't have to estimate a "future annual mileage" figure for the company to obtain a discount. In the event of a traffic stop, an officer could easily verify that the insurance is current by comparing the figure on the insurance card to that on the odometer.

Critics point out the possibility of cheating the system by odometer tampering. Although the newer electronic odometers are difficult to roll back, they can still be defeated by disconnecting the odometer wires and reconnecting them later. However, as the Cents Per Mile Now website points out:

As a practical matter, resetting odometers requires equipment plus expertise that makes stealing insurance risky and uneconomical. For example, in order to steal 20,000 miles of continuous protection while paying for only the 2,000 miles from 35,000 miles to 37,000 miles on the odometer, the resetting would have to be done at least nine times to keep the odometer reading within the narrow 2,000-mile covered range. There are also powerful legal deterrents to this way of stealing insurance protection. Odometers have always served as the measuring device for resale value, rental and leasing charges, warranty limits, mechanical breakdown insurance, and cents-per-mile tax deductions or reimbursements for business or government travel. Odometer tampering—detected during claim processing—voids the insurance and, under decades-old state and federal law, is punishable by heavy fines and jail.

Under the cents-per-mile system, rewards for driving less are delivered automatically without need for administratively cumbersome and costly GPS technology. Uniform per-mile exposure measurement for the first time provides the basis for statistically valid rate classes. Insurer premium income automatically keeps pace with increases or decreases in driving activity, cutting back on resulting insurer demand for rate increases and preventing today's windfalls to insurers when decreased driving activity lowers costs but not premiums.

Automobile insurance in the United States

Coverage available

The consumer may be protected with different coverage types depending on what coverage the insured purchases. Some states require that motorists carry minimum levels of auto insurance coverage in order to ensure that its drivers can cover the cost of damages to people or property in the event of an automobile accident. Some states, such as Wisconsin, have more flexible “proof of financial responsibility” requirements.

In the United States, liability insurance covers claims against the policy holder and generally, any other operator of the insured vehicles provided, do not live at the same address as the policy holder, and are not specifically excluded on the policy. In the case of those living at the same address, they must specifically be covered on the policy. Thus it is necessary for example, when a family member comes of driving age they must be added on to the policy. Liability insurance sometimes does not protect the policy holder if they operate any vehicles other than their own. When you drive a vehicle owned by another party, you are covered under that party’s policy. Non-owners policies may be offered that would cover an insured on any vehicle they drive. This coverage is available only to those who do not own their own vehicle and is sometimes required by the government for drivers who have previously been found at fault in an accident.

Generally, liability coverage extends when you rent a car. Comprehensive policies ("full coverage") usually also apply to the rental vehicle, although this should be verified beforehand. Full coverage premiums are based on, among other factors, the value of the insured’s vehicle. This coverage, however, cannot apply to rental cars because the insurance company does not want to assume responsibility for a claim greater than the value of the insured’s vehicle, assuming that a rental car may be worth more than the insured’s vehicle. Most rental car companies offer insurance to cover damage to the rental vehicle. These policies may be unnecessary for many customers as credit card companies, such as Visa and MasterCard, now provide supplemental collision damage coverage to rental cars if the transaction is processed using one of their cards. These benefits are restrictive in terms of the types of vehicles covered.

Liability

Liability coverage provides a fixed dollar amount of coverage for damages that an insured driver becomes legally liable to pay due to an accident or other negligence. For example, if an insured driver drives into a telephone pole and damages the pole, liability coverage pays for the damage to the pole. In this example, the drivers insured may also become liable for other expenses related to damaging the telephone pole, such as loss of service claims (by the telephone company).

Liability coverage is available either as a combined single limit policy, or as a split limit policy

Combined single limit

A combined single limit combines property damage liability coverage and bodily injury coverage under one single combined limit. For example, an insured driver with a combine single liability limit strikes another vehicle and injures the driver and the passenger. Payments for the damages to the other driver's car, as well as payments for injury claims for the driver and passenger, would be paid out under this same coverage.

Split limits

A split limit liability coverage policy splits the coverages into property damage coverage and bodily injury coverage. In the example given above, payments for the other driver's vehicle would be paid out under property damage coverage, and payments for the injuries would be paid out under bodily injury coverage.

Bodily injury liability coverage is also usually split as well into a maximum payment per person and a maximum payment per accident.

Collision

Collision coverage provides coverage for an insured's vehicle that is involved in an accident, subject to a deductible. This coverage is designed to provide payments to repair the damaged vehicle, or payment of the cash value of the vehicle if it is not repairable. Collision coverage is optional. Collision Damage Waiver (CDW) is the term used by rental car companies for collision coverage.

Comprehensive

Comprehensive (a.k.a. - Other Than Collision) coverage provides coverage, subject to a deductible, for an insured's vehicle that is damaged by incidents that are not considered Collisions. For example, fire, theft (or attempted theft), vandalism, weather, or impacts with animals are types of Comprehensive losses.