Sorry, there is no link for the study afaik. Could get you a copy if pester me for it. Saturation means that, for example, a junction is so full that 'blocking back' occurs. i.e gridlock
TfL don't really know what is going on with cycling rates in London. They know it is increasing, but different measure show it increasing at different rates. What I meant was that the number of being killed or seriosly injured has doubled in ten years. TfL also know that the probability of being KSI conditional on being in an accident is increasing - so not only are you more likely to be in an accident, but you're more likely to be seriously injured.
Cycling is a bit of a difficult policy within TfL at the moment as there are so many divisions with a stake in any findings. So much so, that one part of TfL has successfully managed to refuse releasing survey data to another part of TfL.