What sensor technology did Mitsubishi use for its initial passive distance warning system in 1992?

Answer

Lidar

Mitsubishi Motors originated the concept in 1992 on their Debonair model using a lidar-based distance detection system marketed as 'distance warning.'

What sensor technology did Mitsubishi use for its initial passive distance warning system in 1992?
inventorVehicletechnologysystemadaptive cruise control