If you see a road on the highways maintenance layer that is highlighted green but also has a thick red line running through it, it means the road's maintenance status is partially recorded and should be treated as indicative only.
What the colours mean
Green indicates a road that is recorded as maintainable at public expense (adopted).
Dark red indicates a road that is not maintainable at public expense (unadopted).
Green with a red line indicates that something on that stretch of road is recorded as maintained at public expense, but the underlying dataset does not clearly define exactly which part or the full extent of the maintenance.
Why does this happen?
The highways maintenance layer is sourced from the Ordnance Survey (OS) highways dataset, which is compiled from data provided by local council authorities. Councils sometimes report this data using mixed geometries (such as points or polygons rather than clean line segments). When OS converts this into the line data displayed on the map, it can result in overlapping green and red markings where the coverage is indicative rather than definitive.
In short, the data confirms that some element of that road is maintained at public expense - but it could relate to a specific section, a verge, or another feature - and the precise extent isn't defined in the dataset.
What should I do?
If you need definitive confirmation of a road's maintenance status, we recommend verifying directly with the relevant highway authority or relying on the results of your local highway search.