I don't know if the IBT can implement the contract, but with the vote total I think they would be loath to do so. It seems that from the company prospective we would be at anything but a standstill. They have a fairly friendly contract that has been approved by a large majority of their work force. The money saved from implementation would outweigh the interest earned on money owed on delayed raises.
If the recent vote was also a strike authorization, UPS most likely wont let that strike threat linger for more than a couple of weeks, let alone till 2018. I see them diverting volume from Louisville soon and eventually locking out the remaining employees.