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.

During vehicle submergence, at least 1 window per row of seats shall be able to be opened to allow occupant escape, and shall remain openable for at least 2 minutes from water entry. The vehicle shall be lowered into a water-filled container within a 10-degree horizontal angle in X longitudinal and lateral directions. T0 is counted from when lowering straps slacken and the vehicle floats. After 2 minutes of floating, the window must be opened to its lowest position, or automatically lowered if equipped with automatic window lowering system. Alternative sub-system tests demonstrating window opening functionality under water, in agreement with the approval authority and its designated technical service, are acceptable. The test is fulfilled if the window is open to its lowest position after the test.