It is because the Roadtrip and your phone are still within effective operation range (10 meters). As a result, it is still connected to your phone and will not auto power off. Even if it is disconnected for a while, the speakerphone may reconnect with the phone if it detects motion within operating range.
- Turn Bluetooth off on your phone.
- Completely turn off the car kit by sliding the "OFF/ON/FM" switch into the "OFF" position.
Note: When sets to "OFF" position, the Roadtrip is turned off. Next time you need to use it, you need to manually turn it on by sliding it to "ON"/"FM".