In the context of technology, SPaT (Signal Phase and Timing) over the network refers to the transmission of real-time traffic signal data from infrastructure to vehicles using cellular or cloud-based communication instead of just direct short-range radio. What is SPaT Over the Network?
: Provides current signal states (red, yellow, green) and the residual time remaining for each phase.
: Unlike direct radio, which is limited by line-of-sight and distance, network-based SPaT can reach vehicles much further away, allowing for earlier planning.
Traditionally, SPaT messages were broadcast via , which requires a vehicle to be within a few hundred meters of a physical roadside unit (RSU). SPaT over the network leverages existing 4G/LTE or 5G cellular infrastructure (C-V2X) and cloud platforms to deliver this data.