The premium relief that auto insurers are extending to customers — who are driving much less during the coronavirus pandemic — should be doubled to protect them from overcharges and prevent windfall profits for the insurance companies, two consumer groups say.

In a report Thursday, the Austin-based Center for Economic Justice and the Consumer Federation of America in Washington, D.C., said insurers need to continue providing premium relief for “at least several months” because of the drop in driving and fewer auto accidents following stay-at-home orders.

In the four weeks between March 22 and April 18, car crashes in Texas dropped by more than half from the same period a year ago, data from the Texas Department of Transportation show. CEJ and CFA’s report was based on data from Texas and Massachusetts.

“Because mileage and accidents have fallen by well over 50% percent during the pandemic, the 15% percent refunds most auto insurance companies have promised are not nearly enough,” Birny Birnbaum, CEJ’s executive director and an economist, said in statement.

On ExpressNews.com: Get the latest update on coronavirus and a tracking map of U.S. cases

Average relief of 30 percent is warranted for all premiums paid from the middle of March through May, the report adds.

Birnbaum called on state insurance commissioners to “step up” and make sure “insurers do the right thing.”

The report fails to consider other factors that go into auto insurance pricing, including type of car, increased technology, location where the car is housed, deductibles, coverage, driver’s age and prior tickets, said Camille Garcia, a spokeswoman for the Insurance Council of Texas, which represents insurers.

Risks like theft, hail, tornadoes and hurricanes don’t go away, she added. And accidents still are occurring at high rates in Texas primarily because of “distracted and faster driving,” resulting in fatalities.

“Despite the continued exposures insurers face, premium discounts were one way insurers could directly and positively impact a large number of individuals and families, Garcia said.

CEJ and CFA’s report comes about two weeks after the two organizations issued report cards grading insurers on how they have responded to COVID-19.

Only two of the nation’s 15 largest insurers received an “A” for the relief they’ve provided — State Farm and American Family Insurance.

State Farm, which has the largest market share in Texas, is providing a dividend of roughly 25 percent of premiums from March 20 through May 31. That amounts to about $20 a month for each vehicle insured, the company says on its website.

Texas’ next three largest insurers, and their grades were: Progressive, “C+”; Geico, “D-”; and Allstate, “B.” Geico’s low grade was partly due to the relief not showing up until customers’ renewal. This serves as a penalty on consumers who don’t renew with Geico, the report says.

San Antonio’s USAA, Texas’ seventh largest auto insurer, received a grade of “C+” for initially providing members a 20 percent credit on two months of premiums. Credits started showing up in members’ accounts last week. USAA has since extended the credit another month.

On ExpressNews.com: USAA upping break on members’ auto insurance premiums

Whether that will improve USAA’s grade hasn’t been determined yet.

“But USAA’s action is important and welcome to us,” J. Robert Hunter, CFA’s insurance director, said in an email. He’s a former Texas insurance commissioner.

USAA has been responsive to the evolving crisis and been making “real-time decisions” as it evaluates driving and claim filing, spokesman Matt Hartwig said in an email. It’s returning $800 million to more than 7 million auto policyholders.

In a CNBC interview Monday, USAA CEO Wayne Peacock said the data showing how often crashes occur and how much they cost “are thrown out the window given the demand shock and all of the stay-at-home orders” issued around the country.

USAA generally experienced 40 to 50 percent fewer accidents before a recent “slight uptick” in accident rates, he said.

“There is either a spring fever or a cabin fever in the air,” Peacock said. “We’re noticing … there are more cars on the road. And we’re seeing that statistically in our accident rates as well, just really in the last two weeks.”

With miles ticking up, USAA may see more accident claims and visits to repair shops as people feel more comfortable, Hartwig said. “This may cause some delay in filing claims.”

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CEJ and CFA said they used conservative assumptions about reduced levels of accidents and insurance claims to calculate the 30 percent premium relief that ought to go to drivers.

They also factored in their calculations other COVID-19 assistance insurers are offering customers, such as grace periods for late payments.

Insurance rates, in general, are set to cover future expected claims and expenses. With the pandemic, the assumptions about future claims on rates in effect March 1 “became radically incorrect overnight,” the report says.

The decline in crashes tracks the drop in vehicle miles driven during the pandemic, the report adds. With the lifting of stay-at-home orders underway, claims may vary by state and within states. But future relief will be necessary, the report says.

States’ insurance regulators have “largely been absent” on premium relief, the report adds. It calls on them to take action to “ensure fair treatment of consumers and prevention of windfall profits for insurers.”

The Texas Department of Insurance said in statement that rates have to be “both fair and adequate,” but must be judged over an adequate period of time — generally the length of the policy period.

“We could have a period of lower claims followed by the mother-of-all hurricanes,” the agency said. “We’re watching this closely, but we need more data before reaching any conclusions.”