For years, car features have been moving more toward James Bond and Batman than toward Henry Ford.

Pricey options such as navigation systems and rear-seat DVD players are becoming as commonplace as power windows, air conditioning and rear-window defoggers a decade or so ago.

Now, General Motors Corp. is trying to follow another emerging trend: safety sells. The world's largest automobile manufacturer last week kicked off a national advertising campaign to announce it would be making its OnStar communications system and its StabiliTrak road control system standard equipment on all of its vehicles by 2010.

Although some car experts would quibble about OnStar, GM is pushing both products as safety features that will become as indispensable as seat belts and air bags. That marketing strategy is seen as the company's attempt to distinguish itself from other manufacturers and develop additional revenue streams through monthly fees attached to OnStar after a free introductory year.

GM's push is not all that surprising. Because of improvements in the reliability of all cars, consumers increasingly are buying vehicles based on other amenities -- creature comforts such as cup holders and sound systems or safety elements such as side air bags and sensors to warn drivers they are about to back into a utility pole or another car.

"The standard automobile is a pretty darn good product, which wasn't the case 20 years ago," said Michael S. Flynn, director of the Office for the Study of Automotive Transportation at the University of Michigan Transportation Research Institute. The result is that carmakers are adding extras and features to try and "differentiate themselves from the competition," he said. "All of this stuff is there because the customer wants it ... and the manufacturers need it to justify or command a higher price."

Indeed, some options carry a hefty price tag, with the total frequently accounting for 25 percent or more of the price of a vehicle. For example, a navigation system can cost $2,000. Nissan advertises its Pathfinder SUV as being priced from $24,650 to $36,150 for the nicely equipped version, with four-wheel drive, navigation system, leather seats and the proverbial "more!"

Flynn said part of the reason for more creature comforts in automobiles is that many people are spending more time driving than ever before. Vehicles as a result are being adapted to include elements usually found at home or in the office, such as entertainment systems or plug-in jacks for computer terminals and cell phones.

"There's a natural evolution of home in our vehicles," Flynn said. "Fifty years ago, parents did tic-tac-toe or counting cows to keep the kids entertained. Now it's more passive with VCRs or DVDs."

A lot of vehicle innovations have developed in an attempt to make everything easier for drivers, said Henry Petroski, a Duke University civil engineering professor who last year wrote, "Small Things Considered," a book that looked at the evolution of such products as cup holders.

For example, Petroski said, electronic starters were developed to eliminate hand cranking in early cars. And in the 1950s, electronic turn signals were placed on steering columns so that drivers no longer had to stick their arms out the window to indicate where they were going.

"It's the real and perceived shortcomings of the automobile that drive these changes," Petroski said. "We all drive along thinking, wouldn't it be easier or nice if I could ... and then an engineer finds a way to do it."

Car manufacturers also have been looking for ways to make money from sources other than selling vehicles, Flynn said, leading to a product such as OnStar. In many cases, the only time the manufacturer gets money from a customer is when he buys a vehicle, while dealers or private mechanics make money from areas such as maintenance and repairs.

"[Manufacturers] don't get any of that money," Flynn said. "There's been a move to invade that revenue stream and create a continuing source of income."

As president of AutoHeroes, a company that buys personal cars for customers in the Boston area, Christopher Burdick has seen the explosion of vehicle amenities firsthand. Consumers and manufacturers both have played a role, he said.

"It's the keep-up-with-the-Joneses mentality," Burdick said. "If they have it, then we have to have it, too, whether it's the customer or the manufacturer."

By making OnStar and StabiliTrak standard items, GM is banking on safety as its ticket to more customers.

"There's an old myth in the industry that safety doesn't sell," Flynn said, noting that this theory developed when Ford Motor Co. saw its sales drop in the 1950s after a year-long campaign touting the safety of its cars.

When seat belts were introduced as an option in the late 1950s and early '60s, they weren't very popular. Later, the federal government required belts and shoulder harnesses as standard equipment, but many states such as Pennsylvania had to pass laws to require their use.

Now, Burdick and Tony Langenderfer, another professional buyer for Expert Auto Consultants Inc. in Sarasota, Fla., said more customers are interested in safety features when they consider which vehicles to buy.

Manufacturers "have found safety sells," Langenderfer said. "They want to be the first to have something so they can market it. When you're putting it in all of your cars, you know there has to be a demand for it."

Tony DiSalle, executive director of sales, service and marketing for OnStar, said 85 percent of consumers give very important ratings to items such as front and side air bags, automatic skid control and notification of emergency personnel if an accident occurs.

Right now, OnStar is available on 32 models of GM vehicles. That will increase to 54 models by the end of 2006 and all models -- more than 4 million vehicles annually -- by 2007.

StabiliTrak, which senses when a vehicle has gone out of control in a skid and shifts brake pressure to try to hold a vehicle on the road, will be added a little slower and won't be on all models until 2010.

OnStar has about 1 million customers in the United States and Canada. The basic Safe and Sound package, which includes notification of emergency personnel if air bags deploy, remote door unlocking and remote diagnostic service if a warning light activates, is $16.95 a month.

More expensive packages that include directions and other concierge services can cost as much as $69.95 monthly.

Customers make about 7 million calls a month to OnStar call centers in Charlotte, N.C., Troy, Mich., and Oshawa, Ontario.

OnStar also offers a hands-free telephone service that it claims has a wider range than regular cellular service.

GM charges $695 to install OnStar as an option, plus the monthly operating fee. The company will not "by any stretch of the imagination" raise the price of its cars by that much, DiSalle said, and the standard, basic service will be free to drivers for the first year.

Much like America Online's marketing plan that includes a free year of Internet service with new Gateway computers, GM is counting on customers liking OnStar enough to pay for it after the first year.

"Thank God, not everybody is going to need the emergency service, but it brings that peace of mind," DiSalle said. "It's almost an insurance plan."

StabiliTrak costs about $600 as an option, but GM hasn't decided whether adding it will increase the price of a vehicle. GM says the system is an important improvement because about 70 percent of vehicle fatalities occur when a car leaves the road.

Langenderfer said he recently renewed OnStar for his Audi Quattro, a 340-horsepower performance car, because it lets him "feel secure" in case of an accident. He thinks it's an important move for GM to move ahead with both features without a government order.

Flynn said GM's success at marketing safety will determine whether that becomes the next trend in the car industry. The company is sinking millions of dollars into the advertising campaign and plant modifications needed to add the new features.

"It's fashionable now," Flynn said. "Will it become a long-term theme? I'm not willing to say that yet."