Vehicles circulate through a one-kilometre equivalent road segment. Increase density and watch their spacing shrink while the equilibrium speed falls. A detector gantry connects moving vehicles to speed, density and hourly flow.
• 3D scene parts: One-lane segment; equilibrium traffic stream; detector gantry; fundamental diagram; density ruler. • Controls: Density (5–150 veh/km); Free-flow speed (40–120 km/h); Jam density (150–220 veh/km). • Live readouts: Space-mean speed (km/h); Equilibrium flow (veh/h); Model capacity (veh/h); Mean front-to-front spacing (m); Critical density (veh/km); Density / jam density (%). • Guided experiments: Capacity density; Congested branch; Free road. • Four tabs (visual laboratory, curves and measurements, experiments, learn and assess), a model-verification run, a timestamped event log and a trial report.
v=vf(1−k/kj); q=kv kcritical=kj/2; qmax=vf kj/4 spacing=1000/k metres
Greenshields equilibrium teaching model. No car-following, lane changes, stochastic waves or calibrated capacity prediction. Only representative vehicles are drawn; the ruler and measurements carry physical scale. Try the preset experiments, then compare the live readouts with the equations.
No. Past the critical density, falling speed dominates.
No. q=kv becomes zero when speed is zero.
Greenshields equilibrium teaching model. No car-following, lane changes, stochastic waves or calibrated capacity prediction. Only representative vehicles are drawn; the ruler and measurements carry physical scale.