The Operation Freeflow website is worth a look:
It says: With so many public transport choices this Christmas, there'll be no need to take your car when you're heading out to shop, eat, drink or make merry! Extra buses, trams and trains are being laid on to make your life easier. We've designed this website as a one-stop-shop to help you plan your journey.
Why not Operation Freeflow for the rest of the year?