This report describes laboratory and field operational testing of a proposed adaptive trolley signal priority (ATSP) system. It consists of three sub-systems: onboard sub-system, roadside control sub-system and central control sub-system. The laboratory testing demonstrates the applicability of the communication system and the traffic signal operation system in San Diego, i.e. the QuicNet/4 central control system in the Transportation Management Center and Type 170 controllers at roadside. The proposed ATSP system was able to reduce the number of stops and stop times for a trolley trip. However, the overall performance of the proposed ATSP system was not as successful as expected, with the maximum average reduction on average number of stops and average travel time is less than 15%. Recommendations are made for improvements to the proposed system.