DETROIT (AP) — A public transit system in Michigan is marking Rosa Park’s refusal to give up her seat on a bus to a white man more than 60 years ago by keeping one seat open on every bus in its fleet.

Mlive reports that the Milwaukee County Transit System’s tribute to the civil rights icon began on Sunday and will run through today in honor of Parks’ courageous refusal aboard a city bus in Montgomery, Alabama, on Dec. 1, 1955.

Parks’ act of civil disobedience that set in motion a U.S. Supreme Court decision that outlawed segregation on public transportation. She later moved to Detroit, where she died at the age of 92 in 2005.

This is the fourth year that the transit system has organized an on-board tribute to Parks.