You need to check rotors and brake pads one or both are failing.
This is usually a symptom of excessive run-out (warped) on front brake rotor or rotors.
Tires,inner tie rod bushings, if the steering wheel shakes when brakes are applied - brake rotors warped.
Chattering/vibration at all speeds. Chattering when brakes are applied. Poor fuel economy. Noise.
brakes or belts check those first. a bad belt can fool ya
Warped brake rotors will cause pulsation (or vibrations at high speeds) when the brakes are applied. This may also go on to misalign the calipers and cause other vibration related damages.
You have warped rotors. They will need to be removed and trued or replaced. Causes of this are lug nuts overtightened, or heat from heavy braking at high speeds.
Switch the front wheels to the rear and try it; if the vibration has changed at all you have a tire/wheel problem. It is not uncommon for a shop to miss this problem. Most vibrations like yours ARE tire/whhel problems. sounds like u-joints
the wind!!
The blower motor speed resister is burned out.
I was considering a Lexus RX400h when I realized that it was very inefficient at freeway speeds 65-75 mph. Most of my driving is freeway at high speeds. How does the Toyota Highlander hybrid technology work? Is it still beneficial/cost effective at freeway speeds?
Couple things come to mind. -improper caliper operation -abnormally worn brake pads -rotor plate abnormally worn -even a suspension missalignment
There must be either some air in your lines or a weak brake caliper. If you have new rotors and brakes then your problem lies within your lines or your calipers. The vibration means that your car is not braking even. One of your calipers could be loose and the other one is tight. If air is in your lines, then that means even though your car is coming to a stop, your calipers are not getting enough pressure to squeeze as tight as they should be.