Fuel prices may may have dipped, but the long-term trajectory for oil prices is firmly upward. Aside from environmental concerns, the price of fuel has a real effect on consumer spending and economic growth. When fuel was below $1 a gallon, there was little incentive to dramatically improve fuel economy, especially in vehicle segments where utility and capability were the primary considerations, but with prices sitting firmly above $3 and sometimes $4 a gallon, improved fuel economy has become a major purchase consideration and engineering objective in all vehicle segments -- including fullsize trucks.

For decades, fullsize pickups struggled to hit the 20 mpg highway mark even with lower-power entry-level engines. Manufacturers focused on increasing power and torque, while keeping fuel economy relatively static, something that buyers were perfectly happy with.

Things have changed considerably in the past three to four years, however, and manufacturers have started looking at fuel economy as well. That shift in priorities has led to a number of developments in the fullsize truck market. General Motors introduced its line of XFE and hybrid fullsize trucks and SUVs models in 2008. Ford followed first with the SFE model and, more recently, with the EcoBoost turbocharged V-6. Chrysler has announced the availability of an eight-speed transmission with the new Pentastar V-6 in the upcoming 2013 Ram 1500, resulting in a forecast EPA estimate of 17 city and 24 highway. Chrysler also appears to be actively testing prototype turbodiesel Ram 1500s, trucks that could break the 25 highway MPG threshold.

Getting these improvements has used up most of the easy-to-implement solutions. Six-speed transmissions are now the industry norm and eight-speeds are on the horizon. Aerodynamic efficiency has gone from barely existing to being closely scrutinized and applied. More advanced techniques such as cylinder deactivation and active grille shutters are starting to appear on fullsize trucks. But the last few mpg needed to hit the 30 mpg mark are proving challenging and elusive, thanks in part to the unique functional capabilities required of a truck that passenger cars and crossovers don't have to contend with, specifically payload and towing capacities. Meeting customer expectations for both requires, among other things, a substantially stronger and usually heavier chassis than a passenger car.

In our conversations with representatives from some of the leading manufacturers of fullsize trucks, the issue of improving fuel economy in trucks was met with equal parts pragmatism and determination. The technical capability of achieving the goal was generally not in question. The bigger questions were how soon and at what cost.

Reginald Modlin, Director of Regulatory Compliance for Chrysler, said that the company was closely involved in discussions with regulators in terms of mapping out a reasonable timeframe for achieving the ambitious fuel economy goals. One condition the automakers insisted on is a mid-term review of the regulations and whether or not consumers were accepting of the new fuel-saving technologies. "We were closely involved in discussions with the regulatory bodies. It was a tough discussion. At the end, we had a pretty good idea of what they were thinking. But whatever standard they wish the vehicles to perform to, the customer has to want it. If we fail in getting the customers excited about it, it will be part of the mid-term discussion in '17-'18."

In terms of the probability of a fullsize truck being able to achieve 30 mpg, Modlin sees that benchmark being about a decade out. "Is it rational to think that a truck could get a 30 mpg label? Is it fiction to think in those terms? Not really. I think it could happen by around 2022." But once again, Modlin said, the product has to be attractive and compelling to the consumer, both in terms of capability and cost. "One of the EPA's assumptions, and this is huge, is no reduction in utility of the vehicles. There's a lot of work that goes into what makes that happen. The challenge is getting the hardware cost down to the point where customers will buy it."

Mike Sweers, chief engineer for the Toyota Tundra, said that the core capabilities and expectations truck customers have don't fundamentally change and that any changes in the name of fuel economy can't compromise those traits. "When we start forcing the customer to conform to something we think they should have, rather than what they want, they'll resist. The majority of truck buyers are in a category we call the 'true truckers.' Their tastes and requirements for a full-size truck remain the same. They like traditional design, and expect the same or improved capability."

Tom Wilkinson, with Chevrolet Truck communications, said now that the froth in the fullsize pickup market brought on by low fuel prices in the late 1990s and early 2000s has abated, the market has seen a return to the 'true truckers' cited by Toyota's Sweers. "The fullsize pickup market is once again made up primarily of people who actually use trucks for towing and hauling and these customers have proven reluctant to trade off capability for fuel economy. As long as we can continue to improve fuel economy without decreasing capability, our customers will be happy, so that's what we're working on."

However, Sweers said the market shift of the pickup from being a work vehicle to a primary vehicle for many buyers has resulted in a slight shift in buyers' preferences. "Now, buyers want more creature comforts, and more cab space, and they're expecting fuel economy to come with it." However, Sweers went on to say that lofty window sticker figure is meaningless if the truck can't perform to owners' expectations in real-world conditions. "We focus on combined fuel economy, not just highway fuel economy. The high highway numbers are great for advertising but may not represent a realistic figure for customers."

Wilkinson said GM is pursuing a multi-faceted product strategy that some other automakers have abandoned by dropping smaller truck offerings from their lineup. He cites the competitive fuel economy of the current Colorado, achieved with a nearly decade-old engine design and four-speed transmission. "We are committed to building and selling a new midsize truck based on the global Colorado here in the U.S. A midsize truck can be a more fuel-efficient alternative for someone who doesn't need all the capability of a fullsize pickup. The current 2WD Colorado has an EPA highway rating of 25 mpg with an older engine and four-speed automatic transmission, so there is room for improvement with a new midsize pickup."

Although Ford is aggressively pursuing the engine downsizing strategy with EcoBoost engines across its car and truck lineups, Sweers believes that in the context of a fullsize truck, a downsized, turbocharged engine has its limitations. "The difficulty with a six-cylinder engine in particular, is it still doesn't have the same capability of a V-8. You have more of an issue with heat buildup with turbochargers and the associated issue of heat soak on performance, with the engine management intervening to protect the engine," he said.

Thinking outside the box of conventional fuels, Chrysler's Modlin sees a potentially promising future for natural gas if the issues of infrastructure and availability can be overcome. Although slightly less power-dense than gasoline and consequently less 'efficient' in the conventional sense, the abundance of supply has driven natural gas prices down to record lows, making it an attractive option for some buyers. "We think on a cost-of-ownership basis. The U.S. is to the point where we have so much natural gas supply, we have nowhere to store it anymore. What's great about the partnership we have with Fiat is they sell a lot of CNG product in Europe. If we can figure out how to get the fleet guys to put fueling stations outside their fences, we could see some real infrastructure growth."

Ford, the current sales volume leader in the U.S. light truck market, declined to be interviewed for this feature, only issuing the statement, "We are constantly looking at multiple ways to improve our cars and trucks with innovative technology that improves fuel efficiency and capability. It is too early, however, to discuss specific approaches or solutions that we might use for future products."

How soon we'll see a 30 mile-per-gallon fullsize truck, or who will be the first to sell it, is anyone's guess. The predominant theme heard throughout is that truck buyers want, and often need, uncompromised capability. If that means a small sacrifice in ultimate fuel economy, that's a price most truck buyers seem willing to pay.