The company you choose and the coverage types and levels you select determine your premiums—but so do various facts about you and the vehicles you drive.

Your Driving Record

The accident rate for those who have had accidents in the past few years is far higher than it is for those without accidents. Similarly, the accident rate for individuals with two speeding tickets during a three-year period is twice as high as the rate for drivers with no tickets. It will come as no surprise, then, that your driving record has a big impact on the premiums you’re offered. Drivers who have not caused an accident or had traffic violations in the previous five or six years pay the lowest auto insurance rates; those who have caused accidents or had traffic violations pay higher rates.

It is difficult to predict exactly how one speeding ticket or one accident will affect your premiums. But we estimate that even one speeding ticket in the last five years increases premiums by, on average, 15 to 20 percent. Two speeding tickets produce even larger bumps—an additional 60 percent per year.

Accidents can be even more costly than tickets. We estimate that having one at-fault accident in the last three years will cost most drivers an extra 50 percent in premiums, and two at-fault accidents will more than double most drivers’ annual premiums.

Most companies consider the driving records of everyone driving your car or cars. Therefore, if you have a perfect driving record but your spouse has had violations or accidents, you may not qualify for the companies’ best rates.

Fortunately, insurance companies can’t hold accidents or tickets against you forever. After three to five years, companies cancel penalties for previous accidents and tickets if you’ve been accident- or ticket-free.

Your Experience and Training as a Driver

Driving experience is strongly related to the likelihood of having accidents and claims—and has a big effect on rates.

In Massachusetts, insurers can’t use the age of drivers to set rates, but they can charge higher rates for inexperienced drivers. Companies usually classify drivers according to three length-of-experience levels: inexperienced drivers licensed less than three years; inexperienced drivers licensed three or more but less than six years; and experienced drivers, licensed six or more years. Inexperienced drivers are further classified according to whether they are a vehicle’s principal operator or only an occasional operator.

A principal operator with four years of driving experience can usually expect to pay roughly double the rate of an experienced operator. A principal operator with only one year of driving experience will usually be charged more than three times the rate of an experienced driver. While having an inexperienced driver on your policy as an occasional driver usually doesn’t cause such a large differential, it still dramatically increases the total premium.

If you have children, make them take a driver training course. Most companies offer discounts—typically 10 percent—for inexperienced drivers who have completed an approved driver training course.

Where You Live

Some localities present more chances for accidents, experience a higher incidence of auto theft and vandalism, or have higher repair costs or medical and legal charges than others. These differences sometimes result in higher auto insurance rates in some parts of the Boston area than in others.

The Car You Drive

You probably won’t buy a car based on insurance costs, but the differences among cars are often substantial: It costs $200 or more per year to insure some cars than others.

Keeping an old car, or buying used, can also substantially affect your premiums. For example, premiums on a seven-year-old car are usually about 12 percent lower than on a five-year-old car. If your car isn’t worth much, you’ll save a lot by dropping collision and comprehensive coverage, since a total loss of your car won’t add up to much more than your deductible.

Your insurance premiums also slightly decrease if your car is equipped with safety devices or anti-theft features. Companies offer a 25 percent discount on PIP, Medical Payments, and Uninsured/Underinsured Motorist coverages for cars with passive restraint systems (air bags or automatic seatbelts). If your vehicle has anti-theft devices, your company must discount your comprehensive coverage by five to 36 percent, depending on the type of device.

Big Breaks for Seniors

If you are age 65 or older, make sure your premium reflects an important discount. All insurers must offer policyholders age 65 or older a 25 percent discount off their total premium if there are no inexperienced drivers on the policy and their cars are not customarily used for business purposes.

How Much You Drive

If you drive your car 5,000 miles a year or less, companies cut your premium by 10 percent (except on the portion of the premium for comprehensive, substitute transportation, and labor and towing coverages). Most companies also offer small discounts if you drive between 5,001 and 7,500 miles.

Length of Time Insured by the Company

If you are considering switching insurance companies, and have been “loss free” with your current company for a while, calculate in any future longevity discounts. Many companies offer renewal discounts each year. Some offer five to 10 percent discounts for three years of coverage without an at-fault accident, and may increase the discount at six years and nine years.

Dual-Policy Discounts

Some companies love to tout the big discounts you’ll get by signing on with them to insure both your cars and home. Some knock off five percent, 10 percent, or even more from either the auto rate or the homeowners rate; some knock off a percentage from both. But keep in mind that dual-policy discounts usually are offered by companies that charge high prices for coverage. A 15 percent dual-policy discount isn’t really much of a discount if it’s offered by a company that charges twice as much as its competitors.

From a consumer’s point of view, this dual-policy pricing is an undesirable practice because it makes shopping more difficult; to find out the exact savings you could realize by switching companies, you have to shop for both types of coverage at once. Click here for our evaluations of homeowners insurance companies.

Other Discounts

Several insurers offer five to 15 percent discounts to groups—employees of specific companies and members of employee associations, alumni associations, and others. But remember that even with a 15 percent group discount, companies that offer these discounts rarely beat the lowest-priced companies for most drivers. But checking on available group discounts might lead you to an insurance company that you would prefer for service or other reasons, but would be unacceptably expensive without a group discount.

If you regularly use mass transit, some companies offer a 10 percent discount on property damage and collision coverages if you provide evidence that you purchased at least 11 months of commuter passes.

Some companies also give discounts for inexperienced drivers who are full-time students and have good grades (typically a B average or better).