Rosa Parks’ refusal to surrender her bus seat to a white passenger and her ensuing arrest and $10 fine in December 1955 was the spark that ignited the mass boycott of Montgomery’s public transit system by African-Americans.
The next day, the Montgomery Improvement Association (MIA) was formed, aiming to continue the boycott under the guidance of a young minister, Martin Luther King, Jr.
Montgomery’s busing system at the time mandated that whites take the seats in the front rows and African-Americans occupy the rear rows. Ultimately, when the two sections would meet, the black people sitting nearest to the front were required by law to get up and make space for white passengers.
The boycott developed into a crippling financial burden for the city, since African Americans constituted “at least 75 percent of the bus ridership,” according to History.com.
Eventually, on November 13, 1956, the US Supreme Court ruled that the state’s busing segregation laws were unconstitutional.