A design is intuitive when users understand and use it correctly and efficiently without needing instructions or prior training. Key signs include matching user expectations, requiring little explanation, giving clear feedback, minimizing thinking, maintaining consistency, and building on familiar patterns. For emergency door opening, intuitive design requires interior release control to unlock doors and unlatch without separate controls. Alternative actions for power loss must be fully intuitive, integrated or in close vicinity, within reach, and properly marked. Exterior door handles need a proper force application area for at least four fingers of an adult hand.