If you look at Hyde Park here on the Wikimedia Maps instance, you can see a multitude of yellow roads, which one would assume of are the same class. This is incorrect, as you can see when viewing the same area on OpenStreetMap (OSM Carto rendering), you can see three different classes of road, primary (highway=primary), secondary (highway=secondary) and motorways (highway=motorway). This causes a huge amount of roads with same thickness and assumed class to appear, when they should be rendered different.
Note that motorways may look thicker, but they are still rendered the same, Wikimedia Maps just combines the roads when they are close together.
How could this be addressed?

• We could render the roads with different colours/thicknesses. E.g. Dark yellow/orange for Motorways/Highways/Trunk, Slightly dark yellow for primary roads and standard yellow for secondary roads. We could also render in the same colour scheme as OSM Carto, though that likely wouldn't go to well with the Mapbox Bright/Wikimedia Maps style
• Open to any ideas...