Hi Red_The_Impaler:

___You are if your Prius II is in stealth mode which is where it should be. You will pay for it later with the recharge however

___The reason 33 - 35 miles per hour on a relatively flat and windless road in a Prius II or Insight 5-speed work so well is that they are at a minimum RPM and power to keep the car from decelerating and maximum gear ratio to keep the RPM’s at their minimum. You would be surprised to see the heat losses of a gear train as RPM’s rise … At 15 miles per hour, you are probably not pushing the highest ratio and the ICE would be lugging severely if it was.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net