With the increasing aging population, more individuals are expected to use assistive devices such as wheelchairs and push carts. For these users, the smoothness of road surfaces and the presence of steps significantly affect safety of their movement. Existing studies have estimated road surface conditions using sensors deployed on vehicles, but they are limited in observational range. Therefore, this study proposes a road surface monitoring system that utilizes sensors embedded in smartphones and enables the collaboration of nearby devices through short-range wireless communication. When a smartphone detects vibrations based on acceleration data, it requests the surrounding devices to capture and analyze images to identify the cause. The analysis is performed on the device, and only the result is sent to the server, which reduces privacy concerns. This system allows collaborative detection across multiple users’ devices without dedicated devices, making it scalable and cost-effective for inclusive road infrastructure monitoring.