## 5 Discussion  
This study employed CiteSpace to conduct a bibliometric analysis of wearable technology research for VRU safety. To address RQ2 and RQ3, we have integrated our previous analyses of specific VRUs (pedestrians, two-wheeler users, and visually impaired pedestrians) to provide a more comprehensive understanding of the temporal evolution of research themes and technological focus areas for VRUs as a whole. This integrated perspective  
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Reference** & **Year** & **Interface Technology** & **Experimental Validation Method** \\ \hline [PERSON] et al. [29] & 2021 & AI edge computing wearable with smart unsglasses, waist device, intelligent cane, and BT earphones & Testing with 1150 zebra crossing images; compared deep learning models with SSD\_Inception\_v2 showing best results \\ \hline [PERSON] et al. [65] & 2021 & Smartphone vision system with Raspberry Pi haptic feedback glove using finger vibration actuators & Testing with 15 blindfolded subjects in three tasks; evaluated real-time navigation with pedestrians, traffic lights, and stop signs \\ \hline [PERSON] \& [PERSON] [59] & 2022 & Wearable RGB-D camera system with Jetson Xavier and bone conduction headphones using maps and SLAM & Testing with three visually impaired subjects at crosswalks; evaluated localization, signal detection, guidance, and walking speed maintenance \\ \hline [PERSON] et al. [66] & 2022 & Chest-mounted camera system with tactile gloves using compressed YOLOV3 and Neural Compute Stick 2 & Testing with three blindfolded subjects across 45 trials in three obstacle scenarios (stationary/multiple/moving) \\ \hline [PERSON] et al. [76] & 2022 & Micro-servo-motor ultrasonic obstacle detection system with median and Kalman filtering for smartphone-based outdoor blind navigation & Testing with prototype device in various urban environments; analyzed detection performance with different obstacle types, including fixed, moving, and special case obstacles \\ \hline [PERSON] et al. [77] & 2023 & Millimeter-wave wearable antennas with synthetic aperture radar for electronic travel aid in medium and short distances & Comparative testing of eight different wearable antenna designs using both FMCW and SFCW radar technologies \\ \hline [PERSON] et al. [5] & 2023 & Chest-mounted stereo camera with grid-based obstacle selection and audio feedback & Field testing in cluttered indoor scenes; evaluated ZED2 camera and Jetson Nano system with lightweight YOLOv5 model \\ \hline [PERSON] et al. [60] & 2024 & Helmet-mounted RGB-D camera with 3D spatialized audio system for blind navigation using visual-auditory substitution & Field testing with blindfolded participants in three different urban environments \\ \hline [PERSON] et al. [78] & 2024 & Handheld AI device with ultrasonic sensors, camera, and audio feedback & Testing with 47 participants in real-life scenarios; evaluated compact device with YOLOv3-based detection using DarkNet-53 backbone \\ \hline [PERSON] et al. [67] & 2024 & Belt-mounted system with camera vision and ultrasonic sensors with vibration feedback & Proof-of-concept prototype demonstration on wearable belt using Linux-embedded computer with Python-based image processing \\ \hline [PERSON] et al. [8] & 2025 & Dual-modality feedback system with bHaptics Tactosy vest and head-mounted LED arrays for street-crossing guidance crossings) & Comparative testing with 32 blindfolded participants across two scenarios (traffic signal-controlled and vehicle-based crossings) \\ \hline [PERSON] et al. [6] & 2025 & Glasses-based wearable obstacle avoidance device with multimodal sensing and cross-modal learning & Field testing with 12 visually impaired participants across multiple indoor and outdoor environments over seven months \\ \hline \hline \end{tabular}
\end{table}
Table 9: _Cont._enables us to more effectively identify emerging patterns and potential future research directions, thereby contributing to the advancement of knowledge in this critical field.