How we check a roundabout

1. Draft. A first version of the junction is read from OpenStreetMap: its shape, arms and lanes.
2. Correct. A person fixes the lane counts, draws the lane paths through the circle and decides the right lane for each exit.
3. Check. They compare every route with evidence we are allowed to use: their own visit, open aerial photographs, street-level photos. The kind of evidence and its date are recorded. We never use Google or Apple map imagery.
4. Sign off. A second step, by a person allowed to sign off, records their name and the date. Only then does the junction appear here.
5. Changes. Editing a junction makes a new draft; the checked version stays up until the new one has been checked and signed off too. Every version is kept.

Still to come: a way to tell us when something on the road has changed.