Table 1. Definitions of commonly tested variables used to objectively measure driving ability after orthopaedic surgery.

Variable	Abbreviation	Definition
Reaction time or initial reaction time	RT or IRT	Time from stimulus appearance to start of release of gas pedal
Movement time or foot movement time	MT or FMT	Time from start of release of gas pedal to initial contact with brake pedal
Brake travel time	BTT	Time from initial contact with brake pedal to full depression of brake pedal
Brake reaction time	BRT	RT + MT (time from stimulus appearance to initial contact with brake pedal)
Total brake time	TBT	RT + MT + BTT (time from stimulus appearance to full depression of brake pedal)