[I Drive Too Fast]

From Apple.

To start using Touch ID, you must first set up a passcode on your iPhone or iPad (or a password on your Mac). You must enter your passcode or password for additional security validation:

after you restart your iPhone, iPad, or Mac;

when more than 48 hours have passed from the last time you unlocked your device;

[Chickensoup]

You can always use the phone though, with the pass thingie?