A couple of links on cycle counts and monitoring:
http://www.dft.gov.uk/pgr/roads/tpm/tal/cyclefacilities/monitoringlocalcycleuse
http://www.dft.gov.uk/cyclingenglan...monitoring_best_practice_casestudy_091107.pdf
http://www.trl.co.uk/online_store/r...g/report_research_on_monitoring_cycle_use.htm
Cyclists are difficult to count accurately, because we are less visible, use a greater number of possible routes, including both on and off highway, make non-standard manoeuvres at junctions (as an engineer would see it...) and require more sensitive loops and tubes for automatic counters. It is hard to find places for automatic counters that you can be sure will capture all the cyclists using that route, without being affected by other vehicles or multiple cyclists. A combination of both manual counts and automatic counters is usually advised, the latter helping to calibrate the former.
It is very difficult to identify a 'representative' location when trying to assess cycle use across a wide area and bear in mind that cycle trips are generally much shorter than car trips, so you need much smaller cordons, and more of them, to avoid missing lots of trips taking place within the area. Because cycle counters are very often located to measure the use of recently developed off-road paths, growth care has to be applied in how changes in use measured at that location reflect changes in use more widely- e.g. very often a new route (if it is any good) will show increased use because it has diverted existing trips onto it. It is of course much easier to use automatic counters on off-road routes, because it is easier to set up pinch points that all the cyclists will pass through.
In terms of which road has the highest level of use, I've just checked with a former Oxfordshire transport planner of my acquaintance,
who tells me that they believed this was probably the section across Magdelen Bridge from The Plain, where the three main roads from East Oxford join the High Street. There are few crossings of the river into central Oxford, so cyclists are concentrated a few locations, this being the most important. The figure I've been given (figures perhaps 4 or 5 years old) is that 800 cyclists pass over Magdelen Bridge into town in the morning peak (8am to 9am- a manual count). Given the problems of under counting, this is most likely to be an underestimate. Cycling here is the nearest thing you see to critical mass in an everyday ride: there are too many cyclists for the cycle lane and they spill out several deep on the approach to the junction. Mill Street in Cambridge is another very busy cycling road, but as Cambridge is more permeable, they are not as concentrated at any one location.
Now, given the significant increases in London in the last few years, it is possible that some places are catching up, but cycling's modal share is still a long way short of Oxford and Cambridge, and London is more permeable, so I'd be surprised if anywhere had yet reached the concentrations to be found on Magdelen Bridge. But it would be nice to be wrong on this!
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