Head-Up Display (HUD) interface originally developed for aviation to project aircraft information onto the windshield, has been adopted in the automotive sector for its significant contribution to enhancing driving efficiency. However, the use of HUDs in vehicle applications presents several experience-related challenges, including issues related to the information type, priority, format, colour, font size, and information positioning, all of which affect user experience. This Recommendation specifies general requirements for HUDs and provides design guidelines to ensure the effective presentation of information to through the HUD interface. The proposed requirements are intended to facilitate the systematic implementation of HUD technology in vehicles, promote harmonized design practices, and serve as a reference framework for future HUD design in vehicle applications.