How to model a large number of bicycles in the demand matrix

Cyclists have a greater effect on the circulating carriageway than on the entry. Ideally you would like to say that each bicycle is worth 0.2 PCU on entry but, say, 1.0 PCU when on the circulating carriageway. This can’t be done – but a workaround can help to achieve a similar result. First, run the model with both 0.2 and 1.0 values. The run that uses 1.0 PCU for a cyclist should then be used, setting the site-specific intercept correction to adjust the capacity of the entries upwards to compensate for the fact that the cyclists have a 0.2 PCU effect rather than 1.0 on the entries. i.e. using the difference in capacity between the two runs.

The slope of the linear capacity relationship cannot be changed in ARCADY hence why you want to use a PCU value for cyclists which is appropriate for the CIRCULATING carriageway. N.B. This should work quite well, but it should be remembered that the site-specific variation is making a FIXED difference in the entry capacities – if the geometries change the difference between the two different PCU runs may change. If significant geometric or flow changes are made the process should be repeated.