Well the cyclist I saw earlier this afternoon was achieving neither of those aims.
Fortunately he was going the other way, but he had over 40 vehicles behind him strung out over a quarter of a mile or so.
The nature of this particular stretch of road means that most of these drivers would have been stuck behind the inconsiderate little turd for several miles.
So the "Congestion" claim fails.
And given that cars grinding along at around 8-12 MPH probabally consume 2-3 as much fuel as they do per-mile than when traveling at 30-40 means that the "Reducing Pollution" one fails too.
Cycling is only beneficial (On ALL counts) if it can be done on completly segrageted highways.
(And yes actually, I would like to see that)