Why do American domestic vehicles have red/ combination brake and turn signals instead of amber indicators?

Question

As a frequent driver in LA/ America in general I’ve always wondered why the NHTSB and DOT let manufacturers have brake lights also be the turn signals on domestic cars when every other country’s cars have amber lights? Can somebody explain this to me like I’m five?

In: Engineering

Answer 1

That’s the minimum, but not the only option. 

All three of our vehicles have amber turn signals in the rear.