The speed limit is 55 MPH, but you'll get killed if you go that slow. Right hand lane is for 60 to 65 MPH, middle lane 65-75 MPH, and left lane for 75 to 85. If you don't mind lane hopping, you can do 100 MPH or better. It's OK to use exit and entrance lanes as passing lanes too. I never see cops pull anyone over. That should make the 125 mile trip about an hour and a half, so throw in a stop for a half hour Mickey Dee's lunch and you've got it in 2 hours.