The interstate is the only place I speed. Too much risk of wrecking anywhere else! On the interstate, I try to keep it at not more than 10% above the posted speed limit. I've been told that's the breaking point in NC & SC, which is where I do most of my interstate traveling between home and Myrtle Beach. I just typically stay with traffic and run with the pack, in the right lane and let some rabbits blow by in the left lane to find the radar!