Human-Centric Study for Setting Optimum Speeds on Speed Bumps Based on Rider Discomfort and Health Risk

Speed bumps are widely implemented as physical traffic-calming measures because of their effectiveness in reducing vehicle speeds. However, they can impose significant discomfort and long-term health risks, particularly for riders of motorized two-wheelers, who are directly exposed to mechanical shocks. This study evaluates these impacts using two physiological metrics: vibration dose value (VDV), representing short-term discomfort, and static compressive stress ( S e ), indicative of spinal stress and long-term health risks. As an exploratory pilot study, field experiments conducted on three speed-bump geometries—350 mm, 500 mm, and 750 mm widths (each 50 mm in height)—suggest a trend whereby VDV decreases with increasing speed because of shorter exposure durations, while S e increases, reflecting heightened spinal stress. To balance these opposing trends, a risk factor ( R ) is introduced to quantify long-term health risk. The study proposes a framework for identifying optimum crossing speeds for each bump geometry, with our study suggesting values of 10 km/h for the 350 mm bump, 15 km/h for the 500 mm bump, and 20 km/h for the 750 mm bump under the stated commuter-exposure scenario. These optimum speeds correspond to a risk factor value below 0.8, indicating a low probability of adverse health outcomes. By integrating comfort and health metrics into a unified risk-based framework, this research provides actionable insights for safer and more inclusive speed-bump design—ensuring speed control without compromising rider well-being.