Hybrid cars have popularized the concept of fuel efficiency since the late 1990s, even though hybrid technology existed a good century or so before that [source: Gitlin]. And hybrids won't be going away anytime soon -- a few luxury and sports car manufacturers are even working on hybrid supercars slated to hit the streets sometime in the next few years. Considering how much the Toyota Prius cost when it first launched, a million-dollar hybrid McLaren or Ferrari might seem like a bargain. Or not.
There are a few simple tricks that manufacturers can use to make the engine more efficient, like variable valve timing for example, which is just a way to time the engine so each cycle of intake and exhaust is as energy efficient as possible. Recent innovations to variable valve timing systems allow the engine to adjust its timing based on driving conditions. Engines designed for such feats are usually found in more expensive cars, but there are ways to reduce costs to make it a more obtainable strategy for the masses. Fuel delivery systems are also undergoing some changes, like adjusting direct injection and compression to get the most power from each cycle. Some engineers are playing around with the differences between gasoline and diesel engines, while others wonder if a gasoline-diesel blend could be the answer to improved fuel economy. Turbo engines are another relatively inexpensive and efficient way to push a lot of power out of a small engine. For instance, a 1.4-liter engine boosted with a turbocharger can produce the same amount of power as a 2.5-liter engine, even though it's a lot smaller and a lot more fuel efficient [source: Gitlin]. European automobile manufacturers have been using the smaller engine and turbo approach for quite a while, and domestic automakers are catching on to its potential.
Start-stop technology is another of the initiatives taking shape, helping reduce a car's fuel consumption at idle by stopping the engine. It's similar to how a hybrid car switches over to the electric engine at a stop, but in this case, the gasoline engine is able to stop and then restart when it's time to go again. This technology requires software that coordinates transmission shifts and prevents the car's electrical systems from draining the battery at a stop. High-tech driver instrumentation is another trend that's predicted to really take off. Real-time fuel monitor gauges help drivers visualize how their driving habits affect fuel economy, which will train them to drive smarter over time. And some GPS systems are equipped to select fuel-efficient routes with fewer stops. And while these features have been trademarks of hybrid cars for years, but there's no reason they can't be implemented across the board.
Cars that sense traffic and automatically adjust to road conditions will be a major improvement; autonomous vehicles are the ultimate "intelligent car" goal. But, until those systems are perfected, there are other steps that can be taken, like borrowing a few ideas from the sports car school of thought. Reducing weight does amazing things for fuel economy, so car designers are studying the tricks that have been used by sports and performance car builders and race teams; things like reducing mass and using light weight high-tech materials (such as aluminum or carbon fiber instead of steel). These moves will help counteract some of the bloat that cars have gained in the past couple of decades -- an estimated 25 percent weight increase over the past 25 years [source: Gitlin]. To truly counteract the fat-car trend, consumers will have to concede that some creature comforts, like heavy powered seats, aren't worth the extra power consumption and weight. (Giving up SUVs entirely would be a massive victory for efficiency, but it's unlikely we'll ever reach that consensus as a society.) The bottom line is, lighter cars perform just fine with smaller engines.
If all that research and design and testing sounds expensive, that's because it is, or it will be, anyway. As mentioned before, the automakers are already a little freaked out by it, although it's still a little unclear how the costs will affect consumers. The Obama administration claims that the 2025 standards will save the average driver $8,200 in fuel over the car's lifespan, but there are still too many variables in play for this to be a guarantee, especially considering no one can predict how much gas will actually cost when that time rolls around. However, 2025 model year sticker prices are estimated to be an average of $8,214 more than 2016 MSRPs, thanks to a combination of updated required safety equipment as well as the new technology that'll make CAFE possible. These numbers are based on a 2010 study with information that might be slightly outdated, but if the estimates are even close, the inflated manufacturer suggested retail prices would wipe out any projected fuel savings. Some of these technologies and vehicle types will have subsidies and other incentives from the government, but it's still a little too early for specific details.
All these changes mean that cars over the next 15 years will look and feel very different from what we now know, even if the particulars are unclear. But if the targets are hit, well, that means good things for the planet. So, just beyond the year 2025, the fuel supply situation should have improved dramatically, but we don't necessarily have to wait that long to see progress. The small (but important) annual 5 percent increases should become more apparent over time, and the entire initiative will be reviewed about halfway through, sometime in 2019. And in the meantime, new and more fuel-efficient cars will be steadily rolled out, trying to get (and stay) ahead of the curve.