They are testing the narrowband programming all week, and should have the switchover completed by the weekend. The repeaters and radios were already programmed, it was just a matter of final on-air testing and getting everyone switched over. The frequencies remain the same, just a change in bandwidth/deviation.
Also, just for the benefit of those who read this thread and don't realize how the Thruway operates...it's not "SP Thruway" you're listening to, it's the entire NYS Thruway Authority on 453.425 and 453.525 (simulcast), which includes NYSP Troop T.