Modeling Regenerative Braking Efficiency in Urban Electric Vehicles as a Function of Initial Braking Speed and Average Deceleration

The growing adoption of electric vehicles (EVs) worldwide has heightened the need to maximize their energy efficiency, particularly in urban settings where frequent stop-and-go driving leads to repeated energy losses during braking. Regenerative braking (RB) systems address this by converting part of the vehicle's kinetic energy into electrical energy stored in the battery. This study isolates two fundamental and observable determinants: initial braking speed and average deceleration. Thirty braking events were reconstructed through a digitization protocol from published 3D plots, and recovery efficiency was defined as the ratio of recovered energy to kinetic energy lost, computed from a baseline vehicle mass of 1400 kg. Outliers were excluded using the IQR rule, resulting in a robust analytic dataset of 24 braking events. The analysis reveals that average deceleration is a statistically significant driver of efficiency, with each 1 m/s² increase associated with an approximate 16.8 percentage point gain, while initial braking speed shows a small, non-significant negative coefficient. Applications to the Modified Indian Driving Cycle demonstrate the practical relevance for urban planning and traffic engineering.