Another important factor in determining car-insurance premiums involves the annual mileage put on the vehicle, and for what reason. Driving to and from work every day at a specified distance, especially in urban areas where common traffic routes are known, presents different risks than how a retiree who does not work any longer may use their vehicle. Common practice has been that this information was provided solely by the insured person, but some insurance providers have started to collect regular odometer readings to verify the risk.
In 1998, the Progressive Insurance company started a pilot program in Texas, in which drivers received a discount for installing a GPS-based device that tracked their driving behavior and reported the results via cellular phone to the company. The program was discontinued in 2000. In following years many policies (including Progressive) have been trialed and successfully introduced worldwide into what are referred to as Telematic Insurance. Such 'telematic' policies typically are based on black-box insurance technology, such devices derive from a stolen vehicle and fleet tracking but are used for insurance purposes. Since 2010 GPS-based and Telematic Insurance systems have become more mainstream in the auto insurance market not just aimed at specialised auto-fleet markets or high value vehicles (with an emphasis on stolen vehicle recovery). Modern GPS-based systems are branded as 'PAYD' Pay As You Drive insurance policies, 'PHYD' Pay How You Drive or since 2012 Smartphone auto insurance policies which utilise smartphones as a GPS sensor, e.g. . A detailed survey of the smartphone as measurement probe for insurance telematics is provided in 
 Availability varies. Enrollment discount applies during data collection; final discount is calculated on driving behavior and could be zero. Discounts do not apply to all coverage elements; actual savings vary by state, coverage selections, rating factors and policy changes. Final discount applies at the next policy renewal and remains until drivers or vehicles on the policy change.
The cheapest car insurance, period, will likely carry the minimum coverage required in your state. In most states, this is liability insurance only, which covers property damage and medical bills for others due to accidents you cause. Some states also require uninsured and underinsured motorist coverage, which pay for your injuries or damage if an at-fault driver doesn’t have enough insurance.
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 affect 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).
Insurance companies have started using credit ratings of their policyholders to determine risk. Drivers with good credit scores get lower insurance premiums, as it is believed that they are more financially stable, more responsible and have the financial means to better maintain their vehicles. Those with lower credit scores can have their premiums raised or insurance canceled outright. It has been shown that good drivers with spotty credit records could be charged higher premiums than bad drivers with good credit records.
In South Australia, since July 2016, CTP is no longer provided by the Motor Accident Commission.The government has now licensed four private insurers - AAMI, Allianz, QBE and SGIC, to offer CTP insurance SA. The scheme allocates one provider for 3 years as part of vehicle registration. After July 2019, vehicle owners can choose a different CTP insurer and new insurers may also enter the market.