Sorry, this is in Swedish, and that isn't my native tongue either..

It's interesting to see that Prius achieves such a good position in this test. I have always thought that because Toyota has optimized Prius' materials to be as lightweight as possible the noise levels would be higher especially on highway speeds.

Best 10 on 90km/h (~56mph)
Lexus LS 600h 65,9 dBA
Mercedes S-klass 68,7
BMW 5-serie 69,1
Volvo V70 69,5
Renault Mègane 69,6
Audi A6 69,9
Volvo S80 70,6
VW Tiguan 70,7
Toyota Prius 71,3
VW Passat 71,4

Another observation is the huge difference in between Lexus and S-class Mercedes, I wonder whether it is really valid.

Worst 10

Citroën C1 77,4
Nissan 350Z 76,8
Ford Focus/Opel Astra 75,2
Skoda Fabia 74,5
Toyota Auris 74,4
Skoda Octavia 74,1
Kia Cee´d 5d 74,0
VW Golf 73,9
Kia Cee´d SW 73,8
Peugeot 308 73,7

The test was only 35 models so it wasn't very comprehensive though.