Sorry for the confusion. I am a chemical engineer. I typed "HDPE" - High Density PolyEthylene" I meant to type "HPDE" - High Performance Driver Education. At CMP there are three run groups on TurnOne track days. A novice group, with instructors and classroom, a solo group and an advanced group. ALL passing is done by point by. In the novice group, passing is allowed on the long straights. In the solo group, anywhere the wheels are "straight" and in the advanced group, anywhere on the track. I run in the solo group.