I rarely hear anyone have questions on the noise level at highway speed. I want to confess that if there is one thing to complain about the 2010 prius, it is the noise on rough highway. The level of noise can be like the heavy hail drops in winter time. Maybe most of you live in states that have better highway quality. Here near the Tacoma Wa, the noise can turn the quality music into another kind of noise. Who needs a better quality sound speakers? I hope Toyota would improve the sound insulation or quality of tire before implementing a better audio quality. Though I enjoy all the new technologies from the new Prius, the noise in some portion of the highway almost makes it intolerable to drive.
Coming from a 2006 Prius, noise level inside the cabin has been much improved IMO. It may not be Lexus-like but from how it was for me this is a great improvement.
It is high, I will agree. A bit more than my 97 Camry. I think most of that is related to the LRR tires. If it bugs you that much, you might consider regular tires as others here have noted to help (with a possible hit to mpg). I think Toyota could have sacrificed a new pounds more for more insulation. But I am realing lov'n my 53 mpg (calculated). That is the main reason I bought it.
This can be best addressed with tires. Even Lexus vehicles have a lot of road noise if they are fitted with loud tires. What PSI are you running in your tires? Higher PSIs generally equate to lower noise. If it REALLY bugs you, you could always have some Dynamat installed underneath the carpeting...
I would think hatchbacks in general would have this problem. It would be interesting to see what additional sound deadening materials over the rear wheel wells would do and how easy it is to install
Provided you know how to remove the interior trim pieces its pretty easy to install. Or you can just pay an audio-installer to install it for you.
I have a 2004 and I had dynamat installed years ago along with running GY Triple Tred tires. I find the noise levels pretty decent with these modifications. I am able to have normal conversations at 70mph with the radio playing and our voices are not raised at all. There are certain types of road surfaces (cement like if you will) that can be noisy in any vehicle. Truth be told, interior sound quality is a big selling point for me in a car. Whenever I read a car review I always look at the interior sound level db at speed and if it is too high I get turned off. Lexus has very quiet interiors in most of their vehicles. Ironically, Mercedes and Audi aren't as quiet inside as you may think. I've owned both and was a but perturbed by the noise levels.
I've seen the front wheel wells, and they are just plastic shells -- they aren't doing much to reduce the transfer of road noise to the cabin. If I drove this car with passengers more often, this really would become a concern. I don't find the road noise objectionable when I am on my own -- I just turn the volume up on the radio. When I have a passenger or passengers, it is a whole different story, and I become very conscious of the type of road surface. It can't be that much of a weight or build cost issue. I assume it is simply one way to allow Lexus to have a different level of cabin comfort.
I have 4000 miles on my G3, IV ... and have been delighted with the interior sound level (very acceptable). From previous experience, I suspect the tires are the greater offender, but my G3 was "undercoated." I suspect that dampened a lot of noise. I traded a 2001 Highlander. The road noice was terrible. Finally the tires wore out, and I installed a set of Michlean tires. It completely transformed theh car. Better handling, and the sound level was signaficantly improved.