Drivers in the year 2025 could save as much as $8,000 over the course of their vehicle's lifespan if it meets Corporate Average Fuel Economy standards, according to a report by the Consumers Union.

The report compared estimated costs for a 2025 model year vehicle to existing standards for the 2016 model year. It also takes into account the likely incremental price increases for technology upgrades, insurance and maintenance costs, and expectations for gas prices.

CAFE standards, which are set by the Department of Transportation, were first established in 1975 with the goal of increasing the fuel economy of vehicles over time and reducing energy consumption in the United States. The Environmental Protection Agency says that due to differences in testing procedures, the "window sticker" fuel economy estimates are usually about 20 to 25 percent lower than CAFE figures.

The Consumers Union report says the 2025 CAFE standards are 52.9 miles per gallon for cars and 39 miles per gallon for light trucks. It says these standards represent an efficiency increase of 46 percent for cars and 42 percent for light trucks above 2016 standards.

CAFE standards vary based on the type of vehicle, so small cars must meet higher fuel economy values than those for trucks and SUVs. Automakers can also choose to comply with CAFE standards by having the average fuel economy of the entire new vehicle fleet meet the requirements.

The Consumers Union report says its figures for the 2025 CAFE standards are for the "average fleet-wide achieved" fuel economy. This calculation includes ways to meet standards other than fuel efficiency improvements, including flexible fuel credits, credits for electric and plug-in hybrid vehicles, penalties for not meeting a year's standard, and the ability to carry over compliance credits from year to year. The report says these methods allow for an average achieved standard of 47.4 miles per gallon for cars and trucks combined rather than the combined standard of 54.5 miles per gallon established in 2011.

With base gas prices, the report estimates that car drivers in 2025 will save $2,992 over the vehicle's lifetime compared to 2016 costs. If gas prices are higher than expected, the estimated savings are $5,570.

The report estimates higher savings for truck drivers. It suggests that these drivers will save $4,175 with base gas prices and $7,285 with high gas prices.

Savings can be affected by technology costs as well as gas prices. Consumers Union says that if technology costs are lower than expected and gas prices are high when 2025 CAFE standards are met, car drivers can save $5,700 while truck drivers can save $8,000.

The report says the estimated annual savings will be able to outweigh compliance costs in every year of a typical five- or six-year auto loan. Loan payments account for most of the costs in the first six years, with net savings increasing more rapidly after the loan is paid off and a driver is only responsible for maintenance and insurance costs.

Drivers paying in cash will realize slightly more in savings over the course of the vehicle's lifetime, but will not see savings at the outset. The report says this situation occurs because the CAFE standard compliance costs are not initially offset by fuel savings. For drivers buying a 2025 model year vehicle without financing, Consumers Union estimates that the payback period will be three to five years for cars and two to five years for light trucks.

Figures for compliance costs were based on estimates from both the EPA and the National Highway Traffic Safety Administration. Fuel cost estimates were based on forecasts from the U.S. Energy Information Administration, including a low estimate of $3 a gallon and a high estimate of $4.50 a gallon.

Consumers Union is a division of Consumer Reports dedicated to promoting "new, consumer-friendly policies." The report on CAFÉ standards was prepared for the organization by Synapse Energy Economics Inc., a research and consulting firm specializing in energy issues.