OHP did used to run almost solely 911EP overheads, then for a few years went to all slick-tops. However, recently, they have gone to Sound Off Signal. Now, I don't know if this means they will use them exclusively, but the need for good scene lighting on traffic stops seem to dictate the need for overheads, especially in rural OK. Add that to the fact that OHP uses Chargers almost exclusively and has some rather large and well-built Troopers, and the "lost glass" by having inner bars can be detrimental when you put a 6'4" 250 Trooper in a Charger. I used to work there and I'll put my ears to the ground and see if I can find anything out. I'm interested as well, as I know even in the OKC area, it's not uncommon for a Troop to have to run hot @125 for 45 min to make it to a call 3 counties away..... overheads really to rob a high performance car on the highway. In the cities it's almost negligible, but on the open highway its a considerable issue.