Under the radar: Some trends are obvious enough and visible to all investors. Others are more subtle, but are just as potent, and these often slip "under the radar."

Case in point: the Obama administration's new, higher, fuel-efficiency requirement for vehicles. Basically, by 2016 it will cut auto emissions by one-third while increasing the average fuel economy requirement to 39 miles per gallon for cars and 30 miles per gallon for light trucks.

Despite the onset of the latest high energy price era, it goes without saying that the car will remain the main mode of transportation in the United States as the 21st century progresses.

First mass-produced on a national scale by Henry Ford, subsidized by the construction and expansion of the public interstate highway system after World War II, and immortalized by such films as George Lucas's American Graffiti (1973), the car and car culture is intrinsic to modern American life.

The car fuel alternatives

Cheap oil is not intrinsic, however, and that's a major reason why the nation is exploring car / vehicle fuel alternatives. Many options exist, each with strengths / weaknesses, and currently there's no clear winner.

Hence, in a very real sense, your say in the matter will play an important role in determining what fuel most Americans will use for car transportation in the decades ahead.

There's an upside and a downside regarding major auto companies and the quest to develop vehicles with increased fuel-efficiency.

The upside: Auto makers are positioning themselves to carve out niches in fuel-efficient technology and design, The Wall Street Journal reported Monday (subscription required).

The downside: Auto makers appear to be exhibiting a 'herd mentality' on the current propulsion technology -- hybrid engine cars with both a modest electric power source and a mainstay internal combustion engine.

An electric hybrid focus

Following up on its successful electric-gasoline Prius hybrid, Toyota (NYSE: TM) announced it will make hybrid engine systems available on all models by 2020, The Journal reported. Meanwhile, Honda said it would import new hybrid technology to the U.S. to compete with Toyota and Ford (NYSE: F) plans to double its hybrid lineup next year, and Chevrolet's (NYSE: GM) Volt hybrid that will go on sale in 2010.

Economist David H. Wang said investors and consumers should not be overly optimistic or pessimistic regarding the sector's concentration on electric-fuel hybrids.

Ford, the U.S. auto giant facing perhaps its toughest combination of sector competition and economic headwinds in the company's history, is expected to announce it will build a new, seven-passenger luxury crossover, The Wall Street Journal reported Friday (subscription required).

The new three-row Lincoln MKT crossover is expected to go into production next year, and mirror a 'bustle back concept' displayed at the Detroit Auto Show this year, The Journal reported. Its primary competitors would be the Acura MDX, Audi Q7, and Mercedes R class.

Ford Motor Company (NYSE: F) shares were virtually unchanged on the news, up 2 cents to $5.12 in Friday afternoon trading.

Crossovers are larger cars designed to look and function like SUVs, only with better gas mileage.

Analyst takes wait-and-see approach on crossover

Stock Analyst C. Leonard Bauer said he's reserving judgment on the Lincoln MKT, pending performance, fuel economy, and safety test reviews.

U.S. automakers, late to recognize the sales implications of spiraling gas prices, have started to adjust their business models, in at least one modest respect: some luxury cars are now being designed to run on regular unleaded gasoline, USA Today reported Thursday.

Regular unleaded gasoline, with an 87 octane, typically costs 20-40 cents less than premium gasoline, with a 91 octane.

Ford (NYSE: F) and General Motors (NYSE: GM) are encouraging dealers to promote their no-premium-gas luxury cars' potential, as a selling point for consumers with budgets pinched by $4 per gallon gasoline, USA Today reported Thursday. Ford rose 5 cents to $4.99, while GM fell 15 cents to $10.10 in mid-day Thursday trading.

Auto mechanic Eddie Renn, based in Larchmont, N.Y., said the fact that automakers are manufacturing more cars designed to run on regular gasoline "is an improvement," but he questions why the automakers are using a lower gasoline cost as a selling point for luxury cars. Renn added that his auto repair business is not affiliated with any auto manufacturer.

Does gas price matter for luxury car owners?

"If you're driving a luxury car and you're concerned about a 20 or 30 cent difference a gallon, maybe you shouldn't be driving a luxury car." Renn said. "The luxury car owners who come in here [to his gas station] aren't concerned about the price of gas, I can tell you that."

Renn said most new cars, excluding sports cars and other vehicles, are designed to run on regular gasoline. A higher percentage of older cars -- particularly those built before 2000, require a higher octane, either mid-grade gasoline (also called 'plus') with an 89 octane, or the aforementioned premium gasoline, with a 91 octane.

Coal. Detestable coal.

Politically incorrect coal.

The stuff of Dickens' England. Black-lung disease. Strip-mining. And global warming.

Coal is the 'Rodney Dangerfield of energy forms,' because, like the late comedian, it gets no respect.

Have you ever heard of a positive association regarding coal? As a child in the United States, way back in the twentieth century, you dared not misbehave prior to the holidays, lest you get, coal in your stocking.

(No one ever spoke of a reprimand involving 'getting oil in your stocking.' No sir. Oil is considered 'black gold.')

Well, in the near future you and many others may look favorably on collecting coal, and a lot of it, if current trends continue regarding that other notable energy form, oil.

With oil setting yet another record high Friday of $127.43 per barrel and Goldman Sachs renewing traders concerns about inadequate oil supply growth, economists and business executives are becoming increasingly concerned about gasoline prices in the quarters ahead.

U.S. gasoline prices are already up more than 100% since 2004 to a national average of about $3.78-3.83 per gallon. (Many high-cost zones, such as New York, Boston, San Francisco, and Los Angeles, are already experiencing prices well over $4 per gallon.) By any gauge, gasoline's surge is one for the record books - - rapidly approaching percentage increases registered during the first two oil shocks, in 1973-74 and 1979-80.

Given the run-up, how much higher can gasoline prices rise?

First, some may ask, why the emphasis on gasoline prices? In a nutshell, economists obsess over gasoline prices because, unlike the rest of the developed world, the United States has out-sized per capita energy consumption. That's econospeak for 'Americans use many more gallons of fuel to commute to work, do errands, etc. than their counterparts in Europe and around the world.'

Surveys show that gasoline prices are starting to weigh on consumers' psyches, as well as their budgets, but will the recent price surge propel permanent transportation changes in the nation?

Economist Glen Langan thinks it will, with the pivotal level being prices well over $3 per gallon gasoline. Initially, economists thought the $3 per gallon threshold would compel consumers to cut back consumption, Langan said. This didn't occur, despite gasoline's six to nine month long plateau over $3. A few months and 50-60 cents later, consumers have cut back, and Langan says the permanence of gasoline's stratospheric level is the reason.

Gasoline price psychology

"The cutback is a combination of the old and the new price, but it's mostly a reaction to the old $3 gasoline. Consumers would have cut back then, but they didn't because they concluded that it was temporary, a summer price," Langan said. "But after prices didn't drop and continued to increase early this year, well before the new summer driving season, consumers have concluded that the $3 or higher price for gasoline is here to stay, so they're cutting back accordingly. From a budget standpoint, they're making the right choice."

Speaking at the Los Angeles Auto Show, Ford (NYSE: F) CEO Alan Mulally said the automaker is committed to improving miles per gallon efficiency and reducing emissions via implementing technological advances.

And the technological advances Ford's looking to incorporate to help stabilize its market share? Direct fuel injection, smaller-cylinder engines with turbo charges, lighter weight materials, hybrids, and diesels, among others. Moreover, Mulally said Ford's goal will be to increase fuel economy without sacrificing engine performance or auto safety. Ford's shares drifted three cents lower to $7.95 in Thursday afternoon trading.

In general, analysts were encouraged by Ford's presentation, despite the company's lack of a time-table for efficiency improvements or announcement of changes to specific vehicle models, other than a promise to apply diesel fuel and technology to improve the mpg of its popular but fuel-guzzling F-150 pickups.

Detroit's Big Three, General Motors (NYSE: GM), Ford (NYSE: F) and Chrysler have often been criticized for their bureaucracy, slow decision making, and, at times, outright inertia...even when conditions required bold, decisive action.

There's the joke about the five General Motors executives that go on a camping trip in the Great Midwest. Suddenly, they spot a bear 600 feet away and charging toward where they're seated at the camp site.

Each executive has a rifle and is ready to shoot the bear to defend the campers, and the senior executive says: "Allright, Executives, ready, aim, aim, aim, aim, aim, aim, aim, aim, aim..."

In this week's issue of The New Yorker magazine, writer Elizabeth Kolbert outlines why the car of the future has not arrived. ("Running On Fumes" - Does the car of the future have a future?")

Kolbert documents what many have feared: that two commissions ("projects") between the U.S. Government's Executive Branch, one in the Clinton Administration and one in the current Bush Administration, and automakers General Motors (NYSE: GM), Ford (NYSE: F), and Chrysler, that were supposed to design a high-mileage, next-generation car have, in fact, done very little.