Traffic light (state diagram) Example

Traffic light (state diagram) — State Diagram

A three-state finite state machine for a traffic signal — Red, Green, Yellow — with timer-driven transitions and a poweroff exit to a final state. Introduces UML initial and final pseudo-states, transition labels, and the cyclic structure that makes state diagrams the right tool for reactive systems.

Type State diagramStandard OMG UML 2.5.1 §14 + Harel (1987) statechartEngine schematex-stateUpdated 5/26/2026

The request

“Draw a traffic light state diagram that starts at Red, changes from Red to Green to Yellow on a timer, returns to Red, and can end when power is turned off.”

Then tryAdd a flashing red maintenance state.Change the power-off transition to start from every light state.

Other examples in this family.

Loading drawing…

E-commerce order lifecycle (state diagram) — State DiagramState DiagramOpen →

Loading drawing…

Checkout session with composite state and history — State DiagramState DiagramOpen →

Browse all state diagram templates →