While insurers have different breaking points for these rate changes, you may qualify for a lower rate based on the reduced number of miles you drive. For example, a reduction in the average number of miles you drive a week from 200 to 175 represents a yearly decline from 10,400 to 9,100 miles.

Many consumers would receive a lower price in this situation as insurers sometimes use 10,000 miles as a key break in their pricing structures. Savings will average about 5 percent.

CFA noted that these savings will vary by insurer and that some changes in mileage may not produce savings at all with some insurers.

Savings might be more significant for consumers who are charged higher prices for insurance, such as those who are younger or who live in urban areas. On the other hand, an adult living on a farm who pays only a few hundred dollars for auto insurance will save less.

"Every insurer is different when it comes to mileage discounts," Hunter warned. "We urge consumers to call their insurance companies right away to determine if a change in their driving behavior qualifies them for a lower rate right now," he said. "It is also important that consumers who are driving less shop around before renewing their policy."

CFA also called on state insurance commissioners to undertake a review of auto rates to determine if rate reductions are due as a result of large recent gasoline price increases. CFA noted that during previous gas price spikes, fewer auto insurance claims were filed as gas prices increased.

"Auto claims drop because consumers change their driving habits when gas prices shoot up for a sustained period of time," said Hunter. "Even when the price of fuel then drops, the decline in claim frequency tends to remain. It is crucial that state officials make sure that insurance companies are charging fair rates as the amount they have to pay out for insurance claims drops," he said.