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Transport & Urbanism

How do traffic jams form without any accidents? How are transport networks designed? Agent-based models of traffic flow, from city intersections to airline routes.

🚦 Simulations

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Ant Colony Optimisation (ACO)
Route optimisation through pheromone trails. The same principle is used in traffic optimisation and logistics networks.
Intermediate
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Navigation Algorithms
A*, Dijkstra and BFS — the foundation of GPS navigators and urban transit routing systems.
Intermediate
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Route Optimisation (TSP)
The travelling salesman problem — minimising the length of a route. Applied in delivery logistics and flight scheduling.
Advanced
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Interaction Networks
Self-organising transport networks and their topology. Analysis of hubs, resilience and bottlenecks.
Advanced
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NaSch Traffic Model
The Nagel–Schreckenberg cellular automaton for highways. Phantom jams — traffic jams that appear without any obvious cause.
Intermediate
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Pedestrian Flow
The Social Force Model — pedestrian interaction modelled as social and physical forces. Simulating evacuation and crowd crushes.
Intermediate
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City Growth
A cellular automaton of zoning and density. How compact cities and suburbs affect the transport load.
Intermediate
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Bus Bunching
Bus bunching — buses pull together into groups through positive feedback. The optimal headway and schedule.
Intermediate
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Traffic Intersection
Signal timing and queue theory at a 4-way intersection. Webster formula, Poisson arrivals and level-of-service grades.
Intermediate

📐 Key Concepts

Nagel–Schreckenberg Model
A cellular automaton for traffic: acceleration, braking, random slowdown and position update. Above ρ > ρc, self-organising jam waves appear.
Social Force Model
A pedestrian moves under a goal force Fgoal and repulsive forces from walls and other pedestrians. It explains lane formation and the "faster is slower" effect.
Fundamental Diagram of Traffic
Flow q = ρ·v — the relationship between density ρ and speed v. At the critical density ρc the flow is maximal; above it comes congestion and an abrupt drop in speed.
Braess's Paradox
Adding a new road to a transport network can worsen the average travel time for everyone. It is related to the Nash equilibrium in transport games.
Hub Network Topology
Airline and rail networks have a scale-free topology: a few hubs (nodes) connected to thousands of peripheral nodes. Efficient, but vulnerable to targeted attacks on the hubs.
Ant Colony Optimisation (ACO)
Route optimisation through pheromone reinforcement: τij(t+1) = (1−ρ)τij(t) + Δτij. Convergence to a near-optimal solution without exhaustive search.

📖 Learning Resources

📄 A* Algorithm — Foundation of Navigation Systems 📄 Ant Colony Optimisation — Route Planning

🔗 Related Categories

🚦 Transport simulations have an enormous practical impact: accurate traffic modelling can cut congestion by 10–30% without building any new roads. The phantom jam — a traffic jam that appears "out of nowhere" — is a real phenomenon, demonstrated by Japanese physicists on a ring road back in 2008.

Key Concepts

Topics and algorithms you'll explore in this category

Interactive ModelReal-time browser simulation with live parameter controls
WebGL / Canvas 2DHardware-accelerated rendering in the browser
Mathematical FoundationDifferential equations and numerical integration
Open SourceMIT-licensed code — inspect, fork, and learn
No Install RequiredRuns directly in Chrome, Firefox, Safari, Edge
Educational FocusBuilt to explain the underlying science clearly

Frequently Asked Questions

Common questions about this simulation category

Do these simulations require installation?
No. Every simulation runs entirely in your web browser using WebGL and Canvas 2D. Nothing to install or download — open the page and the simulation starts immediately.
Can I use these simulations for teaching?
Yes — all simulations are designed to be educational and run without an account or login. They are widely used in university lectures, high-school science classes, and self-directed learning. Embed them via iframe or link directly.
What devices do the simulations support?
All simulations work on desktop browsers (Chrome, Firefox, Edge, Safari). Many work on mobile and tablets too, though some physics-heavy simulations benefit from the GPU performance of a desktop or laptop.

About Transport & Traffic Simulations

Traffic flow, congestion, public transit, and mobility networks — live

Transport and traffic simulations model the flow of vehicles and people through infrastructure networks. Nagel–Schreckenberg cellular-automaton highway simulations produce phantom traffic jams that appear spontaneously at moderate vehicle densities with no physical bottleneck — emerging from drivers' reaction-time asymmetry between acceleration and braking. Intersection signal-timing optimisers compute green-phase durations that minimise cumulative vehicle delay using Webster's formula.

Public-transit network models assign passengers to routes using utility-maximising path choice and show crowding effects as frequency changes. Pedestrian evacuation simulations implement the social-force model for crowd dynamics, producing bottleneck clogging and self-organisation of bidirectional flow. These are the same computational tools used by transport planners in microsimulation software (VISSIM, SUMO, MATSim) for road design, signal optimisation, and emergency planning.

Each simulation in this category is built with accuracy and interactivity in mind. The underlying mathematical models are the same ones used in academic research and professional engineering — just made accessible through a web browser. Changing parameters in real time and observing the results is one of the most effective ways to build intuition for complex scientific and engineering concepts.

Every Transport simulation here runs free in your browser, letting you experiment with each interactive Transport model — train scheduling, traffic flow on a highway, bicycle kinematics, ship wake patterns and aerodynamic drag — without installing anything. Adjust parameters, observe real-time results and learn Transport dynamics online at your own pace, whether you are a student, educator or curious researcher. The same equations that govern these 5 simulations are used by civil engineers to optimise signal timings at busy junctions, by rail operators to minimise headways on metro lines, and by naval architects to reduce hull resistance and cut fuel consumption on container ships. Experimenting here builds lasting intuition for how speed, mass and friction interact in the real world.