The 10 most & least expensive states for adding a teen driver to an auto policy [Ranked]

How much your annual policy premium increases when you add a teen driver depends a lot on where you live -- and in some states, it can even double.

InsuranceQuotes.com commissioned a study by Quadrant Information Services to examine the economic impact of adding a driver between the ages of 16 and 19 to a family's existing car insurance policy.

According to the study, families who add a teen driver to their existing auto insurance policy will see an average annual premium increase of 80%, up slightly from last year's average increase of 79%. One of the reasons for premium increases is teens' inexperience, which can lead to more car accidents.

InsuranceQuotes.com notes that teen driving accidents can amount to a large bill. The Centers for Disease Control and Prevention (CDC) says drivers between the ages of 15 and 24 account for 30% (a cost of $19 billion) for the total costs of motor vehcile injuries among male drivers, and 28% ($7 billion) of the total costs of motor vehicle injuries among females.

However, the study found that not all states are created equal when it comes to the cost of insuring a teen driver. The average annual premium increase for individual states ranges from 115% to 17%. The reasons for the variation is complicated, notes InsuranceQuotes.com.

One reason could be how each state regulates insurance differently. For example, Hawaii is the only state that doesn't allow insurance providers to consider age, gender or length of driving experience when determining premiums. States like New York, Michigan and North Carolina tend to have lower increases because insurance is regulated more strictly and rating factors are more stringent.

Differences in weather and climate can also affect premium increases. States with harsh winters leave teens more prone to weather-related accidents, and thus higher auto insurance rates.

High population density and high cost of living can also be a factor in the high cost of teen driver insurance in some states.

Click "next" to see which states are the most expensive to add a teen driver to an existing auto policy, and which are the most affordable. To see where your state ranks, check out the InsuranceQuotes.com and Quandrant study here.