The digital-audio phenomenon has yet to penetrate one place where people spend a lot of time listening to music: behind the wheel. Analysts attribute this to the long product cycles for cars. People keep cars for an average of three years, which is about the time it takes for a new feature to find its way into an automobile. That contrasts with product cycles for consumer electronics devices, which run months instead of years. But a few companies aren't waiting for automakers to build digital-audio players into cars. They're grabbing the wheel and pushing products into the aftermarket. The aftermarket refers to products added to a car after its initial purchase. Visteon and Delphi, the two largest car-parts suppliers, announced earlier this month that they will release digital-audio products into the aftermarket. Visteon has signed an agreement to license an in-car player from Phatnoise and plans on calling it the Mach MP3 Jukebox. It is expected to be available by the middle of the year. Phatnoise will also sell its own in-car player, starting in February, for $549 (£375). Both can be added to the current audio system in a car. The Phatnoise system will use a removable hard drive that can connect to a PC via a USB connection. Music can be downloaded to the hard drive and returned to the car. The hard drives will come in capacities of 5GB to 30GB and will hold hundreds of hours of music. More details to come Delphi demonstrated several MP3 players at the Consumer Electronics Show earlier this month. On Wednesday, a company spokesman said there will be further details by the third quarter. In addition, MP3 player maker Empeg, which was acquired by Sonicblue late last year, will begin selling digital audio players for cars in coming months. They will be sold under Sonicblue's Rio brand in the United States. The products are already available in Europe. The Empeg in-car player, based on a version of the Linux operating system, will have a 600-hour capacity and a hard drive designed not to skip. Aiwa and Kenwood already have in-car CD-R players. However, these don't have hard drives and thus can't directly store MP3s. Aiwa's CDC-MP3 costs $300, and Kenwood's Z919 sells for $700. Bryan Ma, an analyst at IDC, has estimated that 1.5 million MP3 players for the car will be shipped by 2003. "MP3 in cars makes sense because so much music is consumed," Ma said, adding that now it's just a question of when automakers will begin selling cars with built-in MP3 players. Gartner analyst P.J. McNealy agrees. "It's really in the hands of Detroit." The ease-of-use factor will also play a big role in the success of MP3 players in cars. "The convenience of getting music from the home to the car has to be easier. Wireless downloads make the most sense," said Thilo Koslowski, a Gartner analyst who covers the automotive industry. Koslowski expects the wireless networking technology known as Bluetooth to play a role in transferring files but doesn't expect it to be available in cars until 2004. The Internet is changing the face of the music industry forever. Find out more at the MP3 Newsroom. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the ZDNet News forum. Let the editors know what you think in the Mailroom. And read other letters.