A work-zone lane restriction reduces service capacity. The stopped queue length grows from cumulative arrivals minus departures, while an upstream shock-front ruler explains how congestion can propagate against vehicle motion.
• 3D scene parts: Upstream traffic; lane-closure taper; stored queue; moving queue-tail marker; arrival and departure recorder. • Controls: Arrival flow (300–2100 veh/h); Work-zone capacity (200–2200 veh/h); Approach speed (30–110 km/h); Queued density (100–180 veh/km); Initial queue (0–80 veh). • Live readouts: Stored vehicles (veh); Equivalent queued length (m); Queue-tail wave speed (km/h); Cumulative new arrivals (veh); Cumulative departures (veh); Vehicle balance error (veh). • Guided experiments: Growing queue; Clear an initial queue; Balanced flow. • Four tabs (visual laboratory, curves and measurements, experiments, learn and assess), a model-verification run, a timestamped event log and a trial report.
N=N0+A−D≥0; Lqueue=1000N/kjam kup=qarrival/vup w=(qout−qin)/(kjam−kup) qout=capacity when a queue exists
Deterministic point queue and a two-state shock diagnostic. Queue length uses jam-density storage; it is not a full kinematic-wave solver. When the queue is empty, no queue-tail wave is reported. Spatial display is clipped beyond its ruler extent; counts remain unbounded. Try the preset experiments, then compare the live readouts with the equations.
Yes. A traffic wave moves between states, not with an individual vehicle.
Yes. N=N0+A−D.
Deterministic point queue and a two-state shock diagnostic. Queue length uses jam-density storage; it is not a full kinematic-wave solver. When the queue is empty, no queue-tail wave is reported. Spatial display is clipped beyond its ruler extent; counts remain unbounded.