The colors of the lines usually indicate similar classes of information: topographic contours (brown); lakes, streams, irrigation ditches, and other hydrographic features (blue); land grids and important roads (red); and other roads and trails, railroads, boundaries, and other cultural features (black).

It is a different view of traffic outside of the traffic layer. It is only showing where there are slowdowns on your route (Orange and Red). Blue is a normal colour assigned to a suggested route in Google Maps.

This green line marches across OS maps and marks your right of way across country. Specifically, all public rights of way (like footpaths, bridleways etc) are marked using variations of the green dashed line. Waymarked trails are marked in a similar way with green diamonds.

Red: Traffic delays. The darker the red, the slower the speed of traffic on the road.