When the button reads "OFF", the application is not active. This means DriveSafe.ly will not read your messages out loud. To activate DriveSafe.ly and have your messages read out loud, tap the "OFF" button and it will switch to "ON" and turn green.

When the button reads "ON", the application is active and will read your text messages and emails out loud. To de-activate DriveSafe.ly, tap the "ON" button and it will switch to "OFF". This confirms that the ap is not active and will no longer read your messages out loud.

The "Settings" button unlocks a control panel where you can change the behavior of DriveSafe.ly while it is activated.