Complex sentence: Dedicated bus lanes have existed on the Kwinana Freeway since the late 1980s, when a project was set up to decrease bus commuters' travel times into Perth from suburbs south of the Swan River.
Split into simpler sentences: Dedicated bus lanes have existed on the Kwinana Freeway since the late 1980s. In the late 1980s, a project was set up to decrease bus commuters' travel times into Perth from suburbs south of the Swan River.