08 Prius driving characteristics

My 08 Prius can't maintain a center-of-the lane track without constant attention, making long trips on Interstates quite stressful and annoying in a new car. I've brought it to the attention of my dealer's service reps and they merely checked the air in the tires and told me, "well it's not pulling one way or the other, must have been the low air in one tire." I drove it home and discovered it was exactly the same as before. I find it so annoying, I'm planning to sell it if they can't fix it. It might be that this cars' driving characteristics are what they are. Anybody have a similar experience? How do other Prius track on a straight, level, smooth highway? Do they maintain lane tracking without undue attention?

I just may be spoiled by my other car, a Mazda Protege that handles like a formula race car on corners and tracks down a straight road like it is on rails! What a pleasure it is to drive!
- Disappointed Prius owner.

 

Tom,

I'm new at this. I thought thread was something you put a button on with.

Dave_M