SHOZ123,
Thanks for posting this. This is a good safety topic. I had this happen to me in bumper to bumper traffic at 60mph. As you know you can push on the brake peddel with both feet and get nothing but hard peddel.
It was unnerving to say the least. I nursed the car home using the transmission and the emergency brake.
Moral to the story, check the vacuum lines and connections to the power brake booster on a regular basis, say as part of the oil change service.
This is especially true for those who street race! rangerj