Cooperative perception that integrates sensing capabilities from both infrastructure and vehicles can greatly benefit the transportation system in terms of safety and data acquisition. In this project, a prototype of such a system was developed and evaluated by integrating a Lidar-based infrastructure detection system (facilitated with a portable Traffic Scanner, TScan) with an SAE Level 4 connected and automated vehicle (CAV). Vehicle-to-everything (V2X) communication devices were installed on both the TScan and the CAV to enable real-time message transmission of detection results in the form of SAE J2735 Basic Safety Messages (BSMs). The prototype system was validated using a case study. This aimed at improving CAV situation awareness and protecting vulnerable road user (VRU) safety. The field-testing results demonstrated the benefit of cooperative perception from infrastructure sensors in detecting the occluded VRU and helping the CAV plan safer and smoother trajectories.