Abstract:

In order to study the characteristics and risks of lane-changing behaviors of large vehicles，trajectory data of large vehicles in the expressway merging area was collected based on drone shooting and image recognition technology，and lane-changing characteristics and spatiotemporal risks of large vehicles were analyzed.The results indicate that the average value of the lane change duration of large vehicles is 5.28s，the average value of the first half time is 2.60s，the average value of the last half time is 2.68s，and the average value of longitudinal lane change travel distance is 78.12 meters.They all obey Weibull Distribution，and are significantly related to lane-changing speed.The lane change duration and the first half time are significantly related to the distance between the large vehicle and the vehicle in front in the original lane and the distance between the large vehicle and the vehicle in front in the target lane.The first half time is also significantly related to the distance along the lane line.75.40% of large vehicles start to change lanes within 100 meters before the bottleneck section of the merging area，and the occurrence of lane-changing behavior spreads from the outer lane to the inner lane in turn.The ave-rage distance and relative speed between the large vehicle and the vehicle in front in the original lane are the smallest，which are 22.91 meters and -0.90m/s，respectively.If the lane change gap is small，the driver will be more inclined to change lane when the lane change gap shrinks slowly or continuously expands.The large vehicle has the highest risk of collision with the vehicle in front in the original lane，and approximately 15.32% of large vehicles change lanes when they are in an unsafe state with the vehicles in front.

Key words: large vehicle, expressway merging area, lane-changing characteristics, lane-changing risk, lane-changing duration, lane-changing speed, vehicle spacing, collision risk