As he says, it has the potential to be a very useful road but the planners have decided that, for large stretches of this modern dual carriageway, the speed limit should be 40mph.
As I am paranoid about getting points on my licence, I tend to obey speed limits in urban areas and so have tried various techniques to regulate my speed, which is harder than one would expect - primarily due to the fact that the road could clearly safely support speeds much higher.
The technique that works best is simply to drive in a far lower gear than necessary. The increasing engine noise works very well as an alert if one's speed begins to creep up.
As Mr Redwood pointed out in his article, this has the perverse effect of causing more fuel to be burned than is necessary, and probably results in lower air quality for nearby residents I imagine.
There is definitely scope here for the creation of a truly unholy alliance between motorists and environmentalists to campaign for a rule change of mutual benefit. Bring it on!