Traffic generally travels at 70+ on interstates. Just because it is officially mandated means nothing. Most state police, especially in PA will tell you they won’t waste time with a ticket until you are over 73.
I am usually a 75-80 MPH guy on highways but was forced to drive 60-65 last week because I was towing a 3000lb pop up with a 35 year old station wagon in 90 degree heat. Even the rusted out Sanford & Sons looking trucks were blowing by me. When we got home my wife finally asked why I had bothered to use the Radar Detector. I said it was just habit.
Cool, I won't have to worry about tickets for another thirty years.