They crashed a car into a brick wall and the damage was approximately the same as two cars both travelling at 50MPH meeting head on.

As I said, Newtonian physics would expect this result getting closer and closer to the same result as the mass of the brick wall increased.

What hasn't been done and would NOT show the same result is a car travelling at 50MPH crashing into a stationary car.

Read up on Newton's Laws of Motion and the conservation of energy to see why 😉