title: Detect when android device is in a moving car
body: <p>For a personal project, I'm trying to detect when an android device is with someone driving.  I initially thought of using GPS to determine average velocity, but decided that would consume power and requires that the user has GPS enabled at all times.  I'd heard that it's possible to tell when someone switches cell towers (on both android and iOS), but is there a broadcast intent for this?  I'm very new to Android development, so was hoping I could register a broadcast receiver to run when I believe the device is in a moving car.</p>
  
  <p>I'm not sure if I can create my own broadcast intents and I assume I couldn't rely on a background process to always be running since android may kill it if memory is needed.</p>
  
  <p>As a side note, I notice that some apps, like skype, have a background process that restarts itself even if I force kill it.  How do they do this?  My thought would be to have a broadcast receiver for when device moves, turns on, etc. to restart the background process... is that what they do?</p>
  
  <p>Thanks for any info!</p>