Time To Kickdown (TTK) ====================== Description ----------- Please refer to the :doc:`TTM`. Properties ---------- Run-time capability ~~~~~~~~~~~~~~~~~~~ Yes Target values ~~~~~~~~~~~~~ None found Subject type ~~~~~~~~~~~~ Optimal for road vehicles (automated and human), sub-optimal for VRUs Scenario type ~~~~~~~~~~~~~ Overlapping predicted trajectories for a significant time span in the scenario Inputs ~~~~~~ Static/dynamic objects and their state (pose, shape, etc.) at time t, MM for maneuver 'kickdown' Output scale ~~~~~~~~~~~~ :math:`\{-\infty\} \cup [0,\infty]`, time (s), ratio scale Reliability ~~~~~~~~~~~ High, under the assumption that collisions can be reliably predicted Validity ~~~~~~~~ High if used in combination with other criticality metrics, unclear if used exclusively; no sources were found on the validity of examining kickdown maneuvers for threat mitigation Sensitivity ~~~~~~~~~~~ Medium, due to kickdown not always being an actually realizable maneuver, thus high TTK values can be measured in effectively critical scenarios Specificity ~~~~~~~~~~~ Medium, as potentially other feasible threat mitigation maneuvers exist (e.g. braking) even for scenes where TTK :math:`\leq 0` Prediction model ~~~~~~~~~~~~~~~~ Time window ^^^^^^^^^^^ Unbound, but usefulness depends on DMM Time mode ^^^^^^^^^ Linear time