Not long after Parks actions, a district court ruled against Segregation Laws and ordered the state of Alabama to desegregate its buses. The case was appealed by the City of Montgomery Alabama and brought to the US Supreme Court, where the Justices ruled in favor of the District Court ruling to desegregate its buses.
Parks actions which helped start the protest led to a judgment being handed down from the highest court, essentially reaffirming what Parks did that day. The Supreme Court ruled conditions under segregation deprived people of equal protections under the 14th Amendment.
Many say Parks actions that day help start the Civil Rights Movement which eventually led to the 1964 Civil Rights Act.
One seemingly small act by one individualled to great change for all.