1. the act or system of giving advance warning or notification before a main signal or announcement
Usage: chiefly British; technical/formal

1. relating to or denoting a warning or signal given in advance of a main signal or event
Usage: chiefly British; technical/formal

Examples

• The railway system uses presignalling to alert drivers before the main signal.
• Presignalling devices help prevent accidents by providing early notification.
• The presignalling mechanism gave operators time to prepare for the incoming train.
• Modern traffic systems incorporate presignalling to improve safety and efficiency.