SPAT: Signal Phase And Timing

Defines an open interface for two-way communication between traffic signal controllers and mobile devices.

Current movement state of each active phase.

• Safety applications, such as warnings and alerts for crash avoidance, and red light violations.

• Mobility applications to enable dynamic and efficient traffic management.

• Environment applications that allow savings in fuel consumption and reduction in CO2 emissions.

The current state of all lanes at the intersection is provided, as well as any active preemption or priority.

Intersection state.

Movement state:

• Lane set (lanes 9-10 are for movement state 1).

• Current state (green, yellow, red).

• Time until the current signal state changes.

Used in cooperation with a map.

State diagram

They can be used virtually