Complex sentence: The A1307 is classified as a very high risk of casualty route, and a proposal exsists to develop a the route would have a new dual carriage way built from Haverhill to Cambridge, keeping the original road open as a feeder road and local bus stop route.
Split into simpler sentences: The A1307 is classified as a very high risk of casualty route. A proposal exsists to develop the route whereby a new dual carriage way would be built from Haverhill to Cambridge, keeping the original road open as a feeder road and local bus stop route.