The 'new road' will make little difference to the traffic congestion in Marple. it may in fact add to it. Don't get your hopes up. You will still be sat in your 45 minute traffic jam to the M60.
The answer is decidedly not more tarmac but less cars. If there is an answer to vehicular traffic and all its implications, then it is in public transport, our rush hour mentality, obsessions with our cars and our journeys to work. Also our civic leaders and transport planners continue to be reactive, visionless and have no spirit of adventure and consider traffic congestion to be a part of life today, as indeed it has come to be.
I'd have to agree with this point above all others that have been made.
Certainly the traffic in and around Marple is atrocious, but a new road will only add to that traffic in the long run. Experience shows that eventually they just fill up.
I am a firm believer that rush hour traffic can - and should - be reduced by lateral problem solving, education and cultural change, and not by the building of more roads.
I used to work in Spinningfields, Manchester and commuted by train from Marple. I could easily have done that job from home, but had to take 2 hours out of my day to be present in an office. A waste of time, money, and energy. And significantly, someone else I know who lives a few streets away commutes to Spinningfields by car because he doesn't like the trains.
One obvious solution would be, where possible, office workers and clerical staff work from home. At the moment all they do is travel to an office and use a computer that is connected to a network - something they can easily do from home. No travel, no congestion, less money, everyone wins - employers, employees, environment etc. Obviously this isn't suitable for every single situation, but there are many many jobs that can be managed in this way.
Other ideas could be a hierarchy system whereby those who need car transport the most are given priority over more casual drivers in rush hour. How would this be managed? Not sure yet, but the idea is surely worthy of consideration.