Someone just reminded the BCC list of Give Cycling a Push: PRESTO Cycling Policy Guide Infrastructure (PDF). It's definitely not the best of the documents available on the topic. Flicking through again, I noticed this passage, referenced to the CROW manual for Dutch cycling infrastructure, repeats the bizarre line that the LCC have been using, most recently during this week's Street Talks:
Inside the more complex built-up area, it is clearly impossible always to separate users and to avoid conflict situations. Therefore the starting point in the built-up area is conflict presentation. Design the road and cycling facilities in such a way that all road users are visually alerted to potential conflict situations between different types of users. In practice this starting point means that cycling facilities are mixed where possible and separated where necessary.
Most links on the basic cycle network should run through quiet streets with a 30km/h speed limit. This is the safest situation all-round and requires no cycle-specific infrastructure. Mixing should be the default option. On busier roads and complex intersections, especially at high speeds and intensities separation must be preferred.
Which, while sufficiently vague to remain strictly truthful, is going to mislead anybody who isn't familiar with the system being described. As David Hembrow points out, this line doesn't come close to capturing the extent to which the Dutch separate out motor traffic from town centres and residential neighbourhoods. It's like the "not enough room on every street" thing — a banal truth that misses the important point.
I'll bank this line from the document, though, for those at the extremist end of "naked streets" who are happy to state explicitly that making roads confusing is a good thing:Ensure recognizable road categories. Creating recognizable and comprehensible traffic situations is essential for safety. Consistent design solutions on roads with similar functions (in terms of road hierarchy) makes potential conflict situations more predictable for cyclists and other users, while also inciting everyone to behave more predictably.