Traffic, in motion.

Your experiment, your pace. Everything is ready to go. Choose a scene and play with the conditions. Changing the car count or truck share restarts traffic; other controls work live.

A simplified car-following model, not a road-design tool. The merge is a two-lane loop with a work zone. Detector passes count laps, not unique trips. In The lights, cars continue straight and recirculate beyond the view. Main Street carries about twice the traffic of Cross Street; crossings count vehicles that fully clear the intersection. Yellow closes new entry, and the next street waits for the intersection to clear. In The ramp, freeway traffic recirculates while new ramp arrivals enter and leave. Metering releases one driver per green. Courteous drivers make room; aggressive drivers keep their pace. Queued arrivals are included in average speed, so a backup beyond the view still counts. The construction toggle closes the left freeway lane downstream of the ramp.