Only customers on The New Verizon Plan are eligible for Safety Mode.
Safety Mode is an optional feature of the new Verizon Plan that lets you keep using data at reduced speeds after your data allowance is used up for the month. You can stay online without worrying about overage fees. For more information on Safety Mode, check out these FAQs.
To disable, click Disable Safety Mode (from the View usage box at the top) then follow instructions.