The document discusses key considerations for designing successful in-car experiences. It breaks down the car environment into physical, emotional, and cognitive contexts that impact the driver. It then outlines five principles for design: tasks should just work; provide needed information when the driver wants it; let the driver focus on driving; think beyond just speech interfaces; and focus on getting tasks done quickly without extensive time spent on them. The document analyzes common tasks performed in cars, use of navigation devices, and suggests designing with the full car interaction in mind including push-to-talk, interrupt, and visual/auditory feedback functions.