(transport, idiomatic) A rule of thumb for safe driving by which a driver must maintain a two-second distance from the vehicle in front.

a rule of thumb by which a driver may maintain a safe following distance, allowing at least a two second interval behind any vehicle that is directly in front of the driver's vehicle.

(computing, informal) The situation where a computer monitor displays a correct screen image when first switched on, but then quickly blanks out, typically associated with capacitor problems.