Complex sentence: Cedarvale and Humewood are separated by Vaughan road, however just slightly further east is the huge Cedarvale ravine, which was once proposed to be an expressway, which would have been the extension to Allen Road.
Split into simpler sentences: Cedarvale and Humewood are separated by Vaughan road, however just a bit further east is the huge Cedarvale ravine, which was once proposed to be an expressway. This expressway would have been the extension to Allen Road.