With practice, you can glide without completely removing your foot from accelerator to initiate. It is really just a spot in the travel of the accelerator whereby: 1.) the regen is not active and thus slowing the car and 2.) the electric motor nor ICE is being used. At that point, the car is simply "coasting." Because of the Prius phenomenal drag coefficient and the design of the transmission, it will do this very well. In practice, I generally don't worry about the exact glide point so much and just concentrate on staying in the lower half of the Eco range and watch the instant MPG (keep above the halfway point which is 50). Doing this will net you 50 MPG and up pretty consistently. Here are things that I have learned will affect that: speed above 50 mph, high winds, steep hills, cargo. The Prius is most happy in bumper to bumper traffic on flat city streets and highways. This keeps the speed down. I have achieved 66 mpg regularly during a 60 mile across town run in rush hour traffic.
