Hello,
It doesn't seem to exist an uniform way for cantonal road number.
Vaud uses rcrc_ref (rcrc for règlement sur la classification des routes
cantonales) but it seems to be Vaud specific.
For Fribourg, I didn't find the corresponding term and use reg_ref:CH:FR
I didn't find any national tagging schema nor in wiki nor in taginfo.
ref is already used for national road number.
For example, national road no 1 between Domdidier and Avenches have a
cantonal number of 3400 in the Fribourg part and 601a in Vaud part.
Have you already tag a cantonal road number ? witch tag ?
What do you think of harmonizing this ? A format like reg_ref:CH:AB
where AB is the cantonal code in 2 letters ? something else ?
Or maybe it has no interest considering most important missing things ?
Regards,
Marc