Tesla Motors (TSLA) CEO Elon Musk said the electric-car maker is considering adding driverless technology to its vehicles and is discussing the prospects for such systems with Google (GOOG).

Musk, 41, said technologies that can take over for drivers are a logical step in the evolution of cars. He has talked with Google about the self-driving technology it's been developing, though he prefers to think of applications that are more like an airplane's autopilot system.

"I like the word autopilot more than I like the word self- driving," Musk said in an interview. "Self-driving sounds like it's going to do something you don't want it to do. Autopilot is a good thing to have in planes, and we should have it in cars."

Palo Alto-based Tesla is considering such technology as regulators and long-established automakers grapple with when and how it can be used to increase safety and driver convenience. Global automakers such as Nissan Motor and government officials say fully autonomous vehicles may not reach dealer showrooms for a decade, twice as long as Google expects.

Later, Musk wrote a follow-up post on Twitter about Google.

"Am a fan of Larry, Sergey & Google in general, but self- driving cars comments to Bloomberg were just off-the-cuff," Musk wrote. "No big announcement here."

Musk, who has developed a reputation for speaking freely through Twitter and in interviews, said it's possible Tesla could be acquired at some point in the future.

Google founders Larry Page and Sergey Brin, both investors in Tesla before its 2010 initial public offering, have been proponents, with Google demonstrating a driverless fleet of Toyota Prius hybrids equipped with laser-radar devices mounted on the roofs.

Google's approach builds on a push for the driverless-car technology long pursued by the U.S. military's Defense Advanced Research Projects Agency, which held vehicle competitions for carmakers and research labs. Anthony Levandowski, product manager for Google's self-driving car project, has said the company expects to release the technology within five years.

"The problem with Google's current approach is that the sensor system is too expensive," Musk said. "It's better to have an optical system, basically cameras with software that is able to figure out what's going on just by looking at things."

Musk is determined to bring the cost of Tesla's cars down so that the company can sell to mainstream consumers. Tesla's Model S sedan has a $69,900 base price, and Musk says the company still intends to squeeze expenses to offer a model for about $30,000 within a few years.

Tesla slid 6.7 percent to $55.51 at the close in New York, the biggest one-day decline since April 3. The shares have soared 64 percent this year, outpacing the 14 percent rise in the Russell 1000 Index. Tesla has said it will report its first profit from sales of all-electric Model S sedans when the company releases first-quarter results Wednesday.

Google, in an e-mailed statement, declined to comment on Musk's comments.

"We've had some technical discussions with Google" about its Light Detection and Ranging, or Lidar, laser tracking system, Musk said last week, noting that it's an expensive approach that may not prove feasible, Musk said.

"I think Tesla will most likely develop its own autopilot system for the car, as I think it should be camera-based, not Lidar-based," Musk said Monday in an email. "However, it is also possible that we do something jointly with Google."

Musk wrote a follow-up post on Twitter about Google.

"Am a fan of Larry, Sergey & Google in general, but self- driving cars comments to Bloomberg were just off-the-cuff," Musk wrote. "No big announcement here."

Musk, who has developed a reputation for speaking freely through Twitter and in interviews, said it's possible Tesla could be acquired at some point in the future.