found a significant correlation between driver's heart ratio variation and the severity of bridgehead bumping through investigation and driving experiments. The results of the study showed that the driver's heart ratio increased by more than ten times/min when the bumping was severe than when driving was stable [17]. These indicators are indirect and do not directly measure the specific settlement of the bridgehead surface. In addition, different people have different sensitivities to bridgehead bumping, so the results obtained from the experiments are closely related to the experimental population, and it is relatively difficult to obtain standard experimental results. The research on bridgehead bumping is mainly focused on the staggered-step settlement, a step-like settlement at the road and bridge connection. Pavement bumping is added to the Highway Performance Assessment Standards [20]. The standard stipulates the use of section-type equipment to detect pavement bumping. After removing the influence of abnormal values, the extreme difference of pavement elevation within the unit length is calculated with 0.1 m as the sampling interval and 10 m as the statistical unit, and then according to the relevant calculation formula to obtain the pavement bumping index (PBI) [20]. The standard concern is mainly caused by the local pavement bump, depression, and road and bridge abnormal connection of bumping cars, that is, only for the staggered-step platform type bridgehead settlement. The research on the bridgehead bumping caused by the non-staggered-step settlement is still blank, and the scholars and the existing standards only focus on detecting and evaluating the staggered-step settlement. In summary, current research focuses on staggered-step settlement, while studies on non-staggered-step settlement are still lacking. Non-staggered-step settlement lacks abrupt changes in height, making it less sensitive to detection using roughness measurement devices. Moreover, when vehicles pass over areas with non-staggered-step settlement, the vibration response of the vehicle is less pronounced compared to staggered-step settlement, making it challenging to assess non-staggered-step settlement at bridgeheads based on vibration response alone. Therefore, there is a need to establish a new objective evaluation index and evaluation model specifically for non-staggered-step settlement. To address the aforementioned issues, this paper proposes a non-staggered bridgehead settlement detection method based on the settlement point ratio. The method utilizes a vehicular system to collect road images, vehicle travel distance, and longitudinal slope data. Subsequently, the bridgehead settlement point ratio is calculated using the proposed settlement point ratio algorithm. The main contributions of this paper are as follows:  
1. We achieve automatic detection of road longitudinal profile curves using multi-source data. We propose an inexpensive automatic system using an inertial navigation sensor and a line scanning camera to evaluate the differential settlement in bridge approach. 2. We introduce a novel bridgehead settlement evaluation indicator, namely SPR. 3. We perform detection of non-staggered bridgehead settlements based on the proposed bridgehead settlement evaluation indicator. The remainder of this paper is organized as follows. Section 2 introduces the types of bridgehead settlement and the detection techniques employed in this study. Section 3 provides a detailed description of the proposed method. Section 4 presents the experiments, discussions, and analysis. Finally, Section 5 provides a summary of this paper.