Prius ll can be stopped with the engine off, but still run the air condtioner. It's electric. Seems Click and Clack could use a little updating on their Hybrid knowledge. Plus, ALL cars are affected the same way on the highway. The faster you go (especially above 50 miles per hour), the more energy it takes to keep you moving thru the air, thus lower MPG. It seems bigger in a hybrid since going from 50 MPG to 45 MPG is 5 MPG (10 percent less), whereas going from 20 MPG to 18 MPG is the same 10 percent loss, but "only" 2 MPG.

'04 Seaside Pearl #7. Fumoto oil drain, mudflaps, rear bumper scuff protector & rear warn system, compass mirror, EV mode button, 8" subwoofer in right rear cubby & 6" subs under seats, power lumbar in the front seats, Coastaletech hitch w/ Aspen bike/snowboard rack. iPod2car, 2 amps, Alpine component speakers, and DVD video, solid 47 MPG @ 70000 miles.