Polygon to Polygon

[JanisHaumueller]

Hello 
I have created polygons from the surfaces of a light-polluted map above a certain value. I am now trying to select only those that are close to the roads. However, when using the Select by Location tool, I get 0 records to be processed. The same with the use of buffers. 
Many thanks for an answer

[DanPatterson]

Select Layer By Location (Data Management)—ArcGIS Pro | Documentation

coordinate systems are important as per the Useage section.

Are you using a projected coordinate system, which is conformal or equidistant? (and not Web Mercator which is distance useless)

Are you using Within a distance geodesic or Within a distance (planar) option?

which makes it important for the coordinate system being used (see Search Distance comments

[AdrianWelsh]

I agree with Dan about the coordinate systems. Whenever I get zero records like this, it's either a coordinate system issue or a Z-value issue. Can you export your polygon layer to the same coordinate system as the roads layer? That should hopefully solve the problem.