Vehicle lane changing in a nearly saturated fast road segment tends to increase the probability of traffic accidents in the road segment and reduce the speed of the rear vehicles in the target lane. To better analyze the relationship between the target vehicle and the front and rear vehicles in the target lane, this study focuses on the insertion angle of the target vehicle as the research object. Moreover, this study considers influencing factors, such as the longitudinal distance, transverse distance, and speed of the front and rear vehicles in the target lane. This study also adopts aerial photography to capture the flow of the main road of the Xi'an South Second Ring Road, Chang'an University segment. Information regarding the vehicle captured on video, including the speed, insertion angle, and coordinates, is extracted using the software Tracker. The coordinates correlation and speed correlation are analyzed using the software SPSS 2.0. K-means cluster analysis is applied to cluster the insertion angle of the target vehicle, and the insertion speed of the target vehicle. Of the total samples, 89.47% were inserted into the target lane at around 23 degrees or below. The PC-Crash software was used to verify that the collision consequences gradually increased with the increase in collision angle. Therefore, when the insertion angle of the vehicle changes to lower than 23 degrees, the overall road traffic condition is optimal, and no large losses are incurred.