This year, the big hurdle for pickup-truck gas mileage was 20 miles per gallon combined--and two trucks made it.

For 2015, the bar has been raised: The next race is to see which full-size pickup can attain a rating of 30 mpg on the highway portion of the EPA test cycle.

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Versions of the Chevrolet Silverado 1500 and Ram 1500, each with a V-6 gasoline engine, hit 20 and 21 mpg respectively. And the 2014 Ram 1500 EcoDiesel got a combined 23 mpg rating. All three have rear-wheel drive.

The highest highway EPA rating for a big 2014 pickup is 28 mpg, achieved by the 2014 Ram 1500 EcoDiesel with rear-wheel drive--but the highest gasoline number is only 25 mpg, for the Ram 1500 HFE model with a 3.6-liter V-6, an eight-speed automatic transmission, and rear-wheel drive.

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According to trade journal Automotive News, a future version of the new Ford F-150 with its aluminum body has a good shot at hitting 30 mpg highway, but probably not for the 2015 model year.

2014 Ram 1500 EcoDiesel

2014 Ram 1500 EcoDiesel

Doing what writer Richard Truett calls a "back-of-the-napkin calculation," he estimates that even with a new, smaller 2.7-liter turbocharged V-6 EcoBoost gasoline engine, the F-150 will only get to about the same 25 mpg highway rating.

That's partly because Ford will be pairing that downsized V-6 to its current six-speed automatic transmission.

But wait 18 months or so after the aluminum F-150 hits the dealers, and Ford will launch an all-new 10-speed automatic transmission in its big pickup truck.

That, suggests Automotive News, might well get it to 30 mpg highway--perhaps for the 2017 model year or thereabouts.

Regardless of where and when they come in, you're likely to see those high highway number a lot in 2015 truck ads--despite the fact that they're not representative of real-world mileage for most owners.

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If Ford does hit 30 mpg highway, however, Ram won't be standing still. Chrysler executives have pledged to maintain fuel-economy leadership.

2015 Chevrolet Colorado, 2013 Los Angeles Auto Show

2015 Chevrolet Colorado, 2013 Los Angeles Auto Show

As for GM, it'll have a version of its upcoming 2015 Chevy Colorado (and GMC Canyon) mid-size pickups with a 2.8-liter four-cylinder turbodiesel that will be its fuel-economy champ, and it's sure to target 30 mpg highway or more with that model.

Nissan and Toyota? Well, Nissan has already announced that its next Titan will offer a 5.0-liter Cummins V-8 turbodiesel in 2015.

Truett suggests that Toyota may offer the exact same engine in a future Tundra; the company neither confirmed nor denied.

Which probably means, "Yes, we will."

Stay tuned for the Great Race To 30 And Beyond ....

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