With the prosperous development in the vehicle scanning method (VSM), there are many works published since 2004. For the detailed and potential applications of the VSM, two pioneer studies can be referred [1,2]. In this study, a vehicle-bridge system with an adaptive amplifier is proposed to enhance the resolution of frequency identification in the vehicle scanning method. In addition to the investigation of the effect of an amplifier, the pitching responses from the spectra of two wheels are investigated for the first time. It is shown that the higher modes of bridge frequencies can be clearly scanned from the amplifier spectrum by tuning the amplifier frequency to a particular higher-order mode. Nevertheless, such a tuned mass damper effect does not affect the frequency spectra as obtained from the vehicular responses. The pitching effect has shown that the rotational vehicle spectrum has better resolution than the amplifier spectrum for scanning bridge frequencies in the presence of pavement irregularity. Furthermore, the pitching responses have shown the shifted bridge frequencies distinctly in the wheel-center spectra, which indicates that the pitching responses can be potentially used to scan the bridge frequencies, even for higher modes.