What you see isn't what you necessarily get with the government's new fuel efficiency standards.
The Obama administration released new Corporate Average Fuel Economy standards this week, requiring automakers to raise the average fuel efficiency of new cars and trucks to 54.5 miles per gallon by 2025.
But don't expect to see 54.5 miles per gallon dotting the window stickers of every new car anytime soon, or even by the 2025 deadline.
"Bottom line, that isn't what you're going to see," says John O'Dell, senior editor at car-shopping site Edmunds.com. That's because of the way the government measures fuel economy—in more lab-like, less real-world conditions—so the actual mileage goal is closer to about 36 miles per gallon, O'Dell says.
That's not to say, however, that fuel efficiency overall won't increase or that there won't be cars that get 54.5 miles to the gallon or more by 2025, he says.
"There will be something out there with 54.5 miles per gallon or something close to that, but that is not going to be the predominant number," O'Dell says. "The numbers people see are going to be all over the map."
Why? It all comes down to a little semantics and the extremely complex nature of the CAFE standards themselves.
For starters, every car rolling off the assembly line isn't required to have a fuel efficiency of 54.5 miles per gallon by 2025. That figure is just the average fuel economy automakers must deliver across the nation's passenger vehicle fleet by 2025.
"There will be 10 miles per gallon trucks and 50 miles per gallon vehicles," O'Dell says.
While that might still sound like a monumental task, there is some fine print when it comes to the new government standards.
The new CAFE standards, while "tough" according to some experts, give automakers a lot of flexibility. Each manufacturer and its vehicle type has different fuel efficiency targets based on its "footprint" and nothing in the rules say that automakers have to offer and sell vehicles that while more fuel efficient, aren't what consumers want to buy. The plan adjusts the miles-per-gallon targets to match the industry's real-world production tallies and market conditions at the end of the year.
"The goal is flexible and based on their best guess of what the mix of vehicles will be in 2025," O'Dell says.
But if gas falls to $2 a gallon and consumers clamor for Ford Excursions and automakers respond to the demand, targets for fuel efficiency could be pared back substantially. On the flipside, if consumers increasingly demand smaller, extremely fuel efficient cars, the targets could increase.
There are also incentives to introduce alternative fuel vehicles such all-electric cars or hybrids, which entitles automakers to credits, which they can use to offset the inefficiencies of larger, gas guzzling models.
Here's a look some preliminary fuel efficient projections for various vehicle makes and models:
There's another reason why consumers probably won't be seeing an influx of 54.5-miles-per-gallon vehicles anytime soon, and it has to do with the different way the government measures and reports fuel efficiency.
The CAFE standards and National Highway Traffic Safety Administration measure and set targets for fuel efficiency based on efficiency readings taken in decidedly less real-world scenarios. Those government tests are based on steady highway speeds and don't take into account things like air conditioning use or the manic variations in speed most drivers make in an average trip.
That's why the CAFE standards and NHTSA goals—what O'Dell calls regulatory measuring numbers—are higher while the window stickers—which are closer to the actual mileage drivers could expect in more real-world driving conditions—are much lower at around 36 miles per gallon for the nation's passenger fleet.
That being said, even heavy-duty trucks and SUVs will still have to be "incredibly more" fuel efficient by 2025, O'Dell says, adding that even if targets are revised, overall fuel efficiency will still increase.
"Even if you sell all large SUVs, overall fuel efficiency is going to go up," he adds.
Meg Handley is a reporter for U.S. News & World Report. You can reach her at email@example.com and follow her on Twitter at @mmhandley.