Forensic Engineering Analysis And Testing For Speed Reduction In Transient Braking

Abstract

The Speed From Skids Equation Is Derived From The Work-Energy Theorem And Is Often Employed In Accident Reconstruction To Determine A Vehicles Speed At The Onset Of Visible Locked-Wheel Braking Application. The Conventional Use Of This Equation In The Field Of Accident Reconstruction, However, Does Not Yield A Vehicles True Speed At The Onset Of Braking. In Maximum Application Of The Brake Pedal, A Vehicle Initially Undergoes A Transient Brake Phase Prior To Arriving At The Quasi-Steady-State Locked-Wheel Brake Phase. There Is A Reduction Of Speed That Occurs During The Transient Phase Of Braking That Is Generally Not Accounted For In The Reconstruction Of Vehicular Collisions. Accounting For This Reduction In Speed, A Forensic Engineer Can Estimate A Vehicles Speed At The Onset Of Braking And Further Employ The Relative Elapsed Time In Collision Avoidance Calculations. This Study Will Explore A Method To Estimate The Speed Reduction Occurring During The Transient Braking Based On Field Testing.