Complex sentence: The traffic jams in Porthmadog were so frightful already that the level crossing made little difference; the issue has been resolved by the opening of the new Porthmadog by-pass (A487) in September 2011.
Split into simpler sentences: The traffic jams in Porthmadog are so frightful already that the level crossing makes little difference. The issue has been resolved by the opening of the new Porthmadog by-pass (A487) in September 2011.