President Barack Obama announced that new, tough fuel-economy standards will be put in place on U.S. passenger cars, requiring that they achieve an average of 35.5 mpg by 2016. The national standard overrides any plans individual states (such as California) had to set their own rules. In addition to setting the fuel economy requirement, it also establishes a national CO2 vehicle-emissions standard.

We're still trying to figure out what the specific fuel-economy and emissions goals will be for trucks. We're working from estimates and reliable rumors now, and will update you as soon as we know concrete facts. It's likely NHTSA will continue to work with a "footprint" standard to determine what fuel economy and emissions each size vehicle will have to achieve. There will be a separate standard for cars and trucks (we've heard the truck standard will be 30.0 mpg) that will average out to 35.5 mpg, and according to NHTSA (the agency that regulates fuel economy standards), "manufacturers of larger vehicles (i.e., vehicles with larger footprints) would face less stringent standards (i.e., higher CO2 grams/mile standards and lower CAFE standards) than manufacturers of smaller vehicles." The EPA will regulate tailpipe emissions, and we don't know exactly how the two agencies will work together on this.

To give you an idea of where trucks have to get compared with where they are now, we turned to Todd Lassa, Motor Trend's Detroit editor. In a recent blog, he wrote that "for the 2007 model year, cars sold in the U.S. averaged 31.3 mpg and light trucks averaged 23.1 mpg. Keep in mind these numbers reflect a complex equation that takes a car or truck's 'footprint' into account." He also explains that vehicles that do not meet the national standards have to either buy credits from another manufacturer or pay a gas-guzzler tax.

So what does this mean for future trucks?

Well, if the 30.0 mpg standard is accurate, truck makers need to improve fuel economy by an average of 6.9 mpg in the next seven years (they have even less time if you consider that it's too late to do much about the 2010 models), with interim standards coming before 2016. These interim standards will mandate fuel-efficiency improvements of about 5% each year.

It looks like technology that's already in the works—and some already available in today's trucks and SUVs—may be what keep trucks on the road for the foreseeable future, and you won't have to resort to doing big jobs with vehicles that can't handle real work.

For those people who don't need to tow an 11,000-lb trailer or carry a heavy payload, there will direct-injection or turbocharged gas engines, and you can expect four or six cylinders. There may also be options such as stop/start technology, where the engine shuts off at red lights and restarts when you step on the throttle (this feature is already used in hybrids), cylinder deactivation, and low-rolling-resistance tires, among others. In addition, hybrid systems continue to improve, and it may not be the same as with a regular gas V-8, but you can tow a decent-size load with a hybrid truck or SUV.

However, the biggest hope for meeting these goals may be clean diesel technology. Clean-diesel engines offer much better fuel economy than similarly sized gas engines. Also—and this is a huge plus—according to industry sources, clean diesels with aftertreatment systems emit lower levels of CO2 than gas engines with the same displacement. Reaching these standards may be tough, but far from impossible. While this could mean gas V-8s may become more expensive and/or harder to find, this could be the ideal opportunity for diesel engines to truly make their mark, and could save the light-truck market.

One of the biggest questions we still have, though, is how the new legislation will affect 3/4- and one-ton trucks, which are currently exempt from CAFE standards. As long as they remain exempt, the HDs shouldn't have to change much at all. And for now, we'll just hope that's how it stays.