Stumbled across (or otherwise learned of) the Light Pollution Map tool. It features base maps with roads and "radiance" overlays. The light pollution overlays appear to be rather granular, finer than what I've seen in the past. It also supports user input with participants entering their own SQM data.
The recent light pollution overlays were made from "VIIRS DNB Cloud Free Composites" with data from Earth Observation Group, NOAA National Geophysical Data Center.
You can access the interactive map centred on Toronto.