MP3 is a compressed audio file format that allows the creation and transmission of commercial quality sound files at a fraction of their former size. An MP3 file of 3 to 4 MB would be around 50 MB in size if stored as a WAV file. This allows you to put more MP3 tracks--easily over 100--on an audio CD than you can manage with other file formats. The abundance of music on a single disc makes MP3 the perfect format for creating CDs of travelling music for use in your car.
Create an MP3 playlist of the songs you want to burn to CD in your favourite music program. With most music programs, this is as simple as creating an empty playlist, then dragging songs from your music library into the playlist.
Insert a CD-R disc into your computer's CD writer and select the "Burn CD" or "Burn Playlist to CD" option in your music program. CD-R discs are more reflective than CD-RW discs, making them easier for your car stereo to read.
Follow any on-screen prompts to burn the files to CD. Many programs will have you click an additional confirmation button to finalise the burn. If you skip this step, the CD will not play in your car's CD player.
Insert the CD into your car stereo for a test run. In most cases, the disc should play just like a commercial audio CD. If your car stereo can't play the disc but your computer can, your car stereo can't decode MP3 files and you will need to use a different format.
If your music files are in a format other than MP3, you'll need to convert them in your audio program before burning them to a CD. While some car stereos are capable of decoding other formats like AAC or WMA, not all can. Most CD players can decode MP3 files.