Since rosa parks was not the first african american women arrested for bus violation, why did her arrest ignite the boycott?

I’m not sure if this is the answer you want, but from what I gathered, it looks like there had been lots of planning to boycott before this incident. Parks was an active member of this discussion and some think that her refusal to move was a challenge. When she was arrested, African American rights groups such as the NAACP took that as a chance to begin the boycott, which was organized by Martin Luther King Jr.