Morgan, an African American entrepreneur and inventor, created the 3-Position Traffic Signal in the early 1920's.
Here are some more facts about Garret Morgan
Witnessing a traffic accident inspired him to create the 3-Position Signal. He figured there should be a third signal on a traffic post to caution drivers, pedestrians, and horse & buggies they will soon need to stop. Present day we call this a yellow light. His 3-Position Signal was the first to do this, and it was the the precursor to the 3-Light Signal we use today.
He only had a 6th grade education. He was forced to get a job and ended up working for sewing-machine factories. He used this time learn the machines inside and out. He was able to earn enough money to pay for a tutor to continue learning.
He patented an improved sewing machine, and started a repair business. While repairing a machine, he discovered a solution to straighten fabric hairs to make sewing easier. He applied this idea to African American hair, and created a creme. Shortly after, G.A Morgan Hair Refining Company established.