Are electric scooters and PMDs as safe to ride 25/26 as bicycles? II

In Singapore, the Land Transport Authority's efforts to upgrade shared paths and encourage the use of bicycles and personal mobility devices (PMDs) have led to a rise in accidents. However, limited research has examined on the safety aspects of bicycle and PMD riding when carrying loads. This study aims to evaluate and compare the stability and safety performance of bicycles and Power Assisted Bicycles (PAB), by investigating the different load distributions with different riding styles. Stability analysis was conducted on one conventional bicycle, one PAB using a mid-drive motor, and two PABs using a hub motor, under varying load conditions, hand positions, and speeds. Tests included self-stability, straight-line, and slalom maneuvers performed on a TuffTread treadmill at the NTU Transport Research Centre. Angular velocity data about the Z-axis were collected using an enDAQ S4 sensor to quantify handlebar fluctuations. Results showed that stability improves with speed but diminishes beyond 18 km/h. Rear and low-mounted loads provided the most stable responses, whereas front handlebar loads caused the greatest instability. The study concludes that mass distribution and maintaining two-hand control plays a more critical role in stability and safety than overall weight, offering recommendations for future regulation and PAB design within Singapore’s active mobility framework.