In which technique are phases overlapped that would normally be done in sequence?

Critical path is a method for identifying the longest sequence of dependent tasks that determines the minimum project duration, not a technique for overlapping phases.

Lead time refers to starting a successor activity before its predecessor finishes, which is a scheduling relationship - fast tracking describes the broader strategy of overlapping entire phases.

Fast tracking deliberately overlaps phases or activities that would normally be performed in sequence, such as beginning construction before design is fully complete. This compresses the schedule but introduces increased risk because later phases may need rework if earlier phases change.

Project tracking is a monitoring and controlling activity, not a schedule compression technique.