Hi Gerd, I have assumed, that option --check-roundabout gets a new algorithm, the one that you have described. I would prefer that use of "dol/dor" counting was controlled by user and option --check-roundabouts looks prefect for this purpose. I think that flags in IMG should be consistent, the one you have mentioned in NOD and a flag in TRE. So any decision about drive-on-left/right should be taken once and should force setting of both flags. My idea is that user can select following processing: - Automatic detection of left/right by using --check-roundabout with options --drive-on-left/right as a fallback. - Forced setting with option --drive-on-left/right alone. - Default setting when no options are used. Defaults could be taken from LocatorConfig.xml or simply set as drive-on-right (hope this is more common). This description also defines priority of processing, with "dol/dor" counting as a first choice, but only if user set explicit option. -- Best regards, Andrzej