Since mid-2013 you may have noticed that Google Maps UK ceased to use the standard UK map road colours, for example, blue for a motorway and green for a dual carriageway. This is because different countries have different conventions for road type colours so where a map covers several countries confusion arose over the changing colours of equal roads. Google maps now follows its own standards for road colours and applies them globally.
In Map view, orange, yellow, and white differentiate types of roads. Orange indicates motorways, A roads are yellow if they are trunk roads and if they are not they are either grey or white, the same as B roads.
Map view drawbacks
Colorblind users and black-and-white printers cannot distinguish orange, yellow and white.
Satellite view has no colour overlay. To view colours, put your mouse over the Satellite view button and click the "Show Labels" checkbox.
Traffic view allows users to check for delays. This colour scheme indicates the average speed of vehicles travelling on those roads at that time. When active, the Traffic View colour key appears in the upper right-hand corner. Green indicates vehicles travelling more than 80 km/h (50 mph), yellow indicates speeds between 40 and 80 km/h (25 and 50 mph) and red means speeds are less than 40 km/h (25 mph). Grey means there is no data available. Black and red roads indicate traffic may be stopped at points. A yellow construction triangle means road works are causing delays.
Traffic view drawbacks
Many country and suburban B roads roads will not have Traffic view information. These roads may have delays, but Google Maps will not report them.