How does an investment in American families that saves them hundreds of billions of dollars sound? How about saving $800 after you've paid off your new car with a five -year loan?

That is what's at stake in a series of public hearings that have been taking place across the country. The hearings are designed to help the National Highway Traffic Safety Administration and the EPA decide whether to finalize rules requiring America's automotive fleet to average 54.5 miles per gallon (mpg) by the year 2025.

The savings for the nation have been totaled and they exceed over half a trillion dollars. This far exceeds the cost of investing in fuel-efficient technologies. The nation's largest consumer groups-the Consumer Federation of America (CFA) and Consumers Union (CU) - have been speaking up in favor of 54.5 mpg at hearings in Detroit, Philadelphia and San Francisco. The reason is simple: 54.5 mpg will save American families money. In fact, CFA calculates it will save American consumers some $500 billion by 2025.

Gas-guzzling vehicles hit Americans right in the pocketbook-especially now. After years of wild oil price swings, with costs trending ever upward in the long term, gas hit a record average of $3.53 per gallon in 2011. CFA calculates that for the average American family, high gas prices meant spending a record $2,850 on gas last year.

Higher fuel efficiency standards can help. Ensuring cars, SUVs, and light trucks get more miles to the gallon will help buffer household budgets from volatile gas prices.

Americans get it. A recent CU survey found that 93 percent of Americans support boosting fuel-efficiency standards, with 80 percent backing an overall fleet average of 55 mpg by 2025. Seventy-seven percent agree that car manufacturers should produce more fuel-efficient vehicles -- and that the government should increase mileage standards.

CFA figures that with a more efficient fleet the average family will save an estimated $3,000 if they keep the car for ten years.

Almost every major foreign and domestic automobile manufacturer supports the proposed new standard, and so does the United Auto Workers union. The 54.5 mpg standard is also important when it comes to the American automotive industry's ability to compete on the world stage, since it is in line with mileage standards set by other countries that buy a lot of cars.

As consumer advocates we understand the value Americans place on choice. And the new gas mileage standards are designed to protect consumer choice. They grade vehicles' fuel efficiency on a curve, so for example, a large SUV is not expected to get the same mileage as a small economy car. Instead, the standards are designed to spur improvements in fuel efficiency in every category of passenger vehicle, from the largest to the smallest. So Americans will still be able to buy any size passenger vehicle they want. It's just that all of them will be more fuel-efficient.

Earlier this month, the International Detroit Auto Show showed us that automakers are already taking these standards seriously and are incorporating advanced technologies and improvements in the conventional gas engine across all their lineups, touting improved fuel economy as a major selling point.

That kind of choice is important, because Americans have always loved their cars. And they will love them even more when they can drive farther on each gallon of gas.

Mark Cooper is the Director of Research for the Consumer Federation of America. CFA is an association of over 300 non-profit consumer organizations that was established to advance the consumer interest through research, advocacy, and education.

Shannon Baker-Branstetter is policy counsel for the nonprofit Consumers Union, the policy and advocacy division of Consumer Reports.