What color are motorway signs typically?

Motorway signs in Ireland, as well as in many other countries, usually have a blue background with white writing or symbols. This color scheme is specifically used for signs that convey information relevant to drivers on motorways, including directions, service areas, and regulations. The blue background is intended to provide high visibility and clarity, making it easier for motorists to quickly understand essential information while driving at higher speeds on e.g. motorways.

The reason for using blue for motorway signs contrasts with other sign colors, such as red and yellow, which are used for different types of warnings or restrictions. Red backgrounds typically indicate prohibitions or cautions, while yellow backgrounds are often used for temporary signs or warnings about road conditions. Thus, the blue color scheme helps to effectively differentiate motorway signage from other road signs, ensuring that drivers can easily identify and interpret them while on the road.