## 4 Conclusions  
This paper has studied the contact-point response of a stationary vehicle placed on a bridge traversed by a moving load. The stationary vehicle response does not reflect the true vibration of the bridge because it contains its own frequency. Consequently, the  
Figure 21: Dynamic responses for a moving vehicle with a mass of 7200 kg. **(a)** Acceleration response of the 3.18-Hz stationary vehicle, its contact-point, and the bridge, along with **(b)** the acceleration spectra.  
Figure 20: Dynamic responses due to a moving vehicle mass of 7200 kg (**a**) and the acceleration response of the 3.18-Hz stationary vehicle, its contact-point, and the bridge, along with **(b)** the acceleration spectra.  
contact-point response was calculated to eliminate this frequency. The paper investigated the factors that influence the response of the stationary vehicle, such as the stationary vehicle frequency and damping, location of the stationary vehicle, the effects of road roughness, moving vehicle speed and mass, and a longer bridge span. The acceleration responses were compared between the stationary vehicle, contact-point, and true bridge responses. Comparisons were performed in the time and frequency domains. The contact-point response showed good agreement with the true bridge response regardless of the stationary vehicle's frequency, the mass and speed of the moving vehicle, and the bridge length. The frequency domain comparison showed that the stationary vehicle frequency was eliminated in the contact-point response. Moreover, higher frequency modes, such as the third mode of bridge vibration, could be detected using the contact-point response. In extreme cases, such as resonance, the contact-point acceleration signal still shows good agreement with that of the bridge. Higher moving vehicle speeds and masses amplify the bridge's dynamic response; however, the agreement between the contact-point response and the true response of the bridge remains good, regardless of mass or speed.  
The location of the stationary vehicle is important in determining the frequency of the bridge. The contact-point response was able to detect the true response of the bridge regardless of the location. Adding damping reduced the difference between the bridge and stationary vehicle responses, but the contact-point response still provides superior results over the stationary vehicle's response.  
Finally, road roughness is known to be an obstacle in identifying the true bridge response when considering the contact-point response of a stationary vehicle. For the cases of damped and undamped stationary vehicles, the contact-point response had a greatly amplified response with huge discrepancies regarding the response of the bridge. This is because the contact-point response depends on the second derivative of the fluctuating stationary response signal when road surface is considered. Although the stationary vehicle's own frequency was reduced significantly, high noise frequencies due to road roughness appeared in the contact-point spectrum; however, when the contact-point response was filtered by the MAF technique, the results agreed well with those of the bridge. Nevertheless, road roughness still requires further investigation, such as considering different roughness profiles and testing other filtering techniques.  
I.H.: writing, editing, concept and analysis. E.N.: concept and guidance: A.T. and A.E.: Helped in Finite Element modelling and analysis. All authors have read and agreed to the publisher version of the manuscript.  
This research was supported by the Universiti Teknologi PETRONAS Malaysia and Yayasan UTP (YUTP) under Research Grant (Cost Center 015 LC0-056).  
Nor applicable.  
Not applicable.  
The authors declare no conflict of interest.