Most MDOT traffic is on MPSCS ( in my area ) but to tell you the truth I only heard them a handfull of times in the last year I would go ahead and put in the VHF freqs and see what you get .
I dont think you will hear much chatter from them like you would the County Roads Crews or DPW .
Besides the MPSCS talkgroups, in some areas, they also use the I-Tac channels in analog mode.for chit-chat:
I-CALL - 866.0125/821.0125 - Calling
ITAC-1 - 866.5125/821.5125 - Tactical
ITAC-2 - 867.0125/822.0125 - Tactical
ITAC-3 - 867.5125/822.5125 - Tactical
ITAC-4 - 868.0125/823.0125 - Tactical