Narrow Cycle Lane

It's not a good idea to put bikes on the pavement unless it's a rural road with very low footfall, or if the space is available to create a separate cycle track, ideally separated from pedestrians in some unmistakeable way (like on a different level). It sounds like that isn't really the case here though.

How busy is the road and how fast? Looking at the LCC policy guidance that Rachel Aldred and other have developed then bikes shouldn't really be sharing space at speeds over 20mph and traffic volumes over 2000 PCUs a day (Passenger Car Units - very roughly equivalent to 2000 cars a day). If the road really is too narrow to put in a cycle track, then is it possible to cut the volume of traffic overall, perhaps by cutting access to the road? Or can the road be made one way for cars and two-way for bikes? Is the narrowness down to the presence of a parking lane and could parking be removed? Could the white line be removed from the middle of the road and two advisory lanes added to create what is effectively a single-track road? (this is really only suitable for low-traffic roads though). Is there another road that has more space that could be used as a well-signed alternative route? 

On the whole, on fast busy roads a narrow painted cycle lane doesn't add much at all, so it's worth exploring all of these alternatives first. 

I'd say a narrow part isn't a problem. 

Make sure that the cycle lane is continuous and intuitive.

Separate above 20mph

If it does continue on the pavement make the transition as smooth as possible for all cyclists including if you have a trailer or a trike.

If need be, use traffic calming if there is a pinch point so vehicles are forced to slow down (aparently we can't trust motorists to know, let alone abide by the highway code - this is vital, unless courts start banning and insisting on re-tests, we simply shouldn't trust the system now in place to ensure drivers are reliable).

Think in terms of could a 70 year old woman on a shopper bike or an 8 year old with a parent manage?

I don't think the width matters, so long as it's wide enough for a trailer or trike. The more adaptable provision can be the more prevelant it can become. 

Highways often don't even visit a site before designing the road - if you can insist that any new provision is visited by someone who knows cycle provision and is tested and approved by LCC, at least to begin with, things will definitley improve.

All routes should be tested for continiuty, no stretch of road exists without the rider coming from somwhere and is going somewhere else. That's where the routes and strategy come in and you can predict usage.

Qustion 1. No -

Pavements are for pedestrians and they really dislike us riding in their space. See Living Streets: 

http://www.livingstreets.org.uk/pavements-are-for-pedestrians-says-livin...

Pushing cyclists onto the pavement is effectively reallocating road space from pedestrians to motorists and in any case tends to result in rubbish infrastructure for cyclists.  We should not be advocating any measures at the expense for road users that are even more vulnerable trhan ourselves. In this particular case the narrow pavement is inadequate for pedestrian only use let alone contemplating shared use.

Question 2. No -

To see how much worse a 1.5m narrow cycle lane makes conditions for cyclists take a look at:

http://www.warringtoncyclecampaign.co.uk/report/cycle-lanes.pdf