Nighttime Traffic Noise & Sleep Arousal Simulator

Road traffic doesn't need to wake you fully to fragment your sleep — a single pass-by loud enough to cross the brain's arousal threshold for the current sleep stage is enough to trigger a micro-arousal and reset the night's ultradian cycle. This simulator renders a bedroom scene with a sleeper, a road outside the window, and a live hypnogram, and drives a real logistic dose-response model — indoor peak level versus a stage-dependent 50%-arousal threshold — against a Poisson process of passing vehicles. Adjust the outdoor noise level, pass-by rate, and window insulation to see how each maps onto arousal count and sleep efficiency across a compressed 8-hour night, consistent with the WHO Environmental Noise Guidelines' emphasis on nighttime L_night exposure.