Abstract: The indirect measurement method based on vehicle responses, also known as vehicle scanning method (VSM), can be employed to accurately and rapidly obtain the dynamic information of bridges and to assess the performance of bridge structures. Drawing upon existing research on VSM, a theoretical framework and methodology for identifying bridge frequencies using both moving and non-moving vehicles are proposed, and their feasibility is validated through indoor scale-model experiments. This study establishes a theoretical model for a vehicle-bridge coupling vibration system comprising both moving and non-moving vehicles. Analytical solutions for the responses of the bridge and non-moving vehicles in this coupling vibration system are derived, revealing the intrinsic mechanism of using non-moving vehicles to extract bridge frequencies. Numerical models are employed to validate the theoretical formulas and to conduct parameter sensitivity analysis. The feasibility of the method proposed is verified through indoor scaled model experiments. The research findings indicate that compared to commonly used moving vehicles, non-moving vehicles are hardly affected by road roughness and demonstrate their superior accuracy in bridge frequency identification even in noisy environments. Moreover, the performance of non-moving vehicles in extracting bridge frequencies is also influenced by their own suspension stiffness, damping, and parking positions. Particularly, higher vehicle damping effectively attenuates vehicle frequency vibration components, thereby enhancing the effectiveness of bridge frequency identification. Furthermore, when employing the method proposed for bridge frequency identification, it is advisable to avoid placing non-moving vehicles in certain “trap” positions, as this may lead to inaccurate identification of certain orders of bridge frequencies.