Experimental ride comfort assessment of electric kick scooters under urban driving scenarios

Ride comfort represents a critical yet still under-investigated aspect in the design of electric kick scooters, despite their widespread use in urban mobility. This work presents an experimental assessment of vibration-induced discomfort under real riding conditions. Three vehicles with different layouts are tested at constant speeds on representative road surfaces. Dedicated laboratory tests are carried out to characterise vehicle mass properties and tyre radial stiffness and to support the interpretation of on-road vibration measurements. Accelerations transmitted to the rider at the foot-deck and hand-steering interfaces are recorded and processed according to ISO standards for whole-body and hand-transmitted vibrations, enabling an objective and quantitative comparison among vehicles. The results highlight a significant degradation of ride comfort on irregular surfaces and a strong dependence of discomfort levels on vehicle speed. A regression analysis is conducted to relate the measured discomfort indices to key vehicle characteristics and operating parameters. Vehicle speed emerges as the dominant factor influencing the vibration response, while road surface roughness and tyre radial stiffness provide secondary but significant contributions. The proposed regression model captures the main experimental trends across different vehicles, speeds and surfaces, and supports a quantitative understanding of the mechanisms governing ride comfort in electric kick scooters.