Just after topping a hill on an Interstate Highway, both lanes of traffic ahead of us came to a sudden and complete stop. I was in left lane and reacted quickly and applied full braking power and managed to stop a foot or 2 from the rear of the stopped car ahead of us. A few seconds later we were hit from the rear by two cars, one, a Black late model Camry, which almost stopped and a 2nd, a large, new German-maker grey SUV, which never applied brakes, destroyed the black Camry behind us and then destroyed our car, when it hit the left rear and after impact continued pushing the front of the car into the steel cables separating our lane of travel from the oncoming traffic in the other lane of the Interstate, until the steel cables stopped us. Neither the electronic collision alert system, the air bags or the emergency braking system activated. The electronic system in our new Lexus then came on and told us that the collision alert/airbag activation system was defective and to contact our dealer for inspection and repair. However, our car was totalled destroyed and taking it to a dealer for "inspection" was neither possible nor practical, but my wife and I walked away without any known injuries. Lexus was advised of the defect, the extent of damage, and told where car was and invited to inspect it. Not sure if Lexus ever inspected it.