I've noticed that at speeds of 60+ (especially 65+), the Prius control doesn't seem "tight." I wouldn't go as far as saying it has a "shimmy" but it's harder to keep straight on the highway. I absolutely adore my Prius but this bothers me. I had the alignment checked and it's perfect. I know all small cars tend to be less grounded than, say, an SUV, but I'm still curious if this is normal before I take it into the dealer. ETA: Wanted to add that this observation is coming from my comparison of how my former '99 Honda Accord handled. Also drove a Honda Fit a while back and don't remember experiencing it either.