Who is the famous African American inventor who invented the Traffic Light in the the early 1900?

A fraud. Or, to be fair: an error.

Traffic lights were invented in the UK by railway engineer JP Knight (who was neither African nor American) in 1868. They were similar to existing railway signals, so it wasn't that spectacular as inventions go.

The modern electric traffic light was invented by Lester Wire (who was American, but not African ... at least not recently; the "Out of Africa" theory says we're all African in ancestry, so let me just call a spade a spade here: he was white) no later than 1912.

Garret Morgan, who did meet the "African American" (that is, black) criterion, invented a traffic signal (that was inferior in several ways to existing designs - it was manual, and operated by a crank, and there's no reliable evidence it was ever actually even used) in 1923, but it apparently makes some people feel better to think that the traffic light was invented by a black man. The sad thing about this is that Morgan really was an inventor, and invented a personal safety hood and smoke protector to help firefighters and emergency workers breathe which he personally demonstrated the effectiveness of by rescuing some people while using it - a far more important invention than a hand-cranked traffic signal in an age when automatic electric signals already existed.