Running simulations
Simulate mode runs individual vehicles over the lane graph. The engine advances in fixed time steps and is deterministic — the same network, demand and seed always reproduce the same run, which is what makes before/after comparisons meaningful.
Playback
The toolbar holds the playback controls: Play/Pause, Step (advance exactly one tick while paused) and Reset, which returns to time zero with the same seed while retaining the completed run for Analysis. Playback speed ranges from ¼× to 8× real time. The simulation runs in a background thread, so the interface stays responsive while thousands of vehicle decisions happen per second.
How vehicles drive
Vehicle behavior comes from established traffic-engineering models rather than scripted paths:
- Car following uses the Improved Intelligent Driver Model with constant-acceleration heuristics for realistic approach and braking behavior.
- Lane changes follow the MOBIL incentive model, including cooperative yielding at merges.
- Vehicles prepare lanes ahead of turns and exits based on their route, respond to signal phases, and reroute around closures.
- Driver profiles vary the model parameters per driver, so a cautious commuter genuinely follows at longer gaps than an aggressive one.
Watching and reading the run
The left panel shows per-source throughput while the run progresses; the inspector shows live results — generated and completed vehicles, throughput, average speed, average delay and current queues, plus a per-lane queue list. Vehicles can be colored by profile, absolute speed, speed relative to the limit, or current behavior to make patterns visible at a glance.
“Set baseline” marks the current run as the reference to compare later runs against, and results can be exported as CSV or JSON on paid plans. Every completed run is retained for the Analysis workspace — see the next chapter.