Version 1.40.7 now supports NFC tags. The little tags can be bought for around $2-$3 (https://nicegear.co.nz/rfid/nfc-tag-universal-round-sticker/ for example). If you have a phone holder attached to your bike, an NFC sticker inside the holder can be used to start the ATT app automatically as soon as the phone is placed in the holder and paused when the phone is removed.
To use an NFC tag, all you need to do is create a 'Custom URI' record of 'att://activetransporttoolkit.com' using an NFC writer app ('NFC Tools' for example - https://play.google.com/store/apps/details?id=com.wakdev.wdnfc). Note that the record must be a custom URI and start with 'att://' and not 'http://'.
When in the 'pause' state, the GPS is turned off which is different to the 'sleep' state that occurs when a blackout area is entered. In the latter case, tracking resumes when the blackout area is exited as before unless is has become 'paused' while in the area. If the app is in a pause state, tracking will only resume either when an NFC tag is detected or when the pause switch is manually slid in to the tracking position.