Well now that is just lame if thats true. I just noticed that I actually can hear and feel it when driving as well, does that happen to you or is this just my own issue? I am going to go to the dealer later this week to have it checked out and will report back!
Tilani -
Did you visit the dealer yet? I'm curious to know what they said. Usually they can't duplicate (or hear) the issue. A good way to duplicate it for them is to turn the key to the 'on' position (don't start the car) and pump the brakes over and over.
I notice this noise all the time - and believe me others do too. It's especially noticeable on the 400h when in electric/battery mode cruising through the parking lot. People look at my car like 'what the hell is wrong with it?'. Try driving alongside a wall so you can hear the noise reflected back. It happens ~20% of the time when releasing the brake pedal.