Mountain Turtle

I got behind a Prius coming down the mountain today. He was only doing 30-35 mph coasting down the hills and around the curves. My 93 Cavalier was coasting much faster even with the 5 speed in 4th gear. Normally, I coast around 40-50 on these hills and curves. His brake lights weren't on so how come he was coasting so slow?:confused::confused:

Mountain Turtle