1. The common language connotation is preferable over some legal interpretation. Despite being titled "Traffic Sign" , Vienna Convention is still split into chapters of "Traffic Sign" and "Road Marking". Under TSRGD, UK's Traffic Signs  Manual still mentions "on the correct use of traffic
signs and road markings ". https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/773421/traffic-signs-manual-chapter-05.pdf
2. What would be the reason to use `traffic_sign=` , when markings already use `road_marking=` ? They aren't using `traffic_sign=solid_stop_line` . It has been suggested this be continued. https://wiki.openstreetmap.org/wiki/Talk:Key:road_marking#Stroke_details
3.1. `road_marking=` is not freeform text. Language suffixes don't have to apply. `url` is the Urali language. Does `*:url=` need to be banned?   I don't oppose to alternatives eg as in https://wiki.openstreetmap.org/wiki/Key:osak:identifier , but `*:id=` is popular enough now. 
3.2. `traffic_sign:id=` was rejected for many reasons. I voted against the proposal, but the idea isn't bad. 
