Am considering buying a Gen III Prius, but one of the things that bothers me about my parents' Gen II is the amount or road noise. Has anyone who's owned both noticed an improvement in that area with the Gen III? I tried to tell on my test drive but the salesman wouldn't stop yakking at me.
I had a 2005 and, now, a 2010 with approximately the same trim levels. The 2010 trim is a IV. With about a thousand miles experience, the 2010 is considerably quieter on all types of roads. The overall handling is also much improved. I hope this helps.
I own a Gen II 2005 loaded which I also added Dynamatt insulation to in the doors and trunk area to help with noise reduction. I drove a Gen III for 2 days whilemy car was in the shop. Much quieter overall-big improvement. I have to add that tire wear makes a huge difference ion cabin noise. My '05 is getting ready for tires in about 3K miles so they are pretty loud right now. The '10, of course, had new tires on it and they were very quiet.
Just keep a salesman in the front seat. you won't be able to hear yourself think, much less hear road noise.
Driving with lower tire pressure (like 30 psi instead of 35 psi) helps quiet the III's ride, but will hurt gas mileage slightly. It wouldn't surprise me in the least if car dealers employed this tactic.
When we first took a 2010 Prius for a test drive, my wife commented that it was a lot quieter than our 2004 Prius. Now that we got our Prius V, we both agree that the ride is smoother and quieter than our old Prius.