Driving Behavior during Right-Turn Maneuvers at Intersections on Left-Hand Traffic Roads.

In Japan, where vehicles drive on the left side of the road, pedestrian fatal accidents caused by vehicles traveling at speeds of less than or equal to 20 km/h, occur most frequently when a vehicle is turning right. The objective of the present study is to clarify the driving behavior in terms of eye glances and driver speeds when drivers of two different types of vehicles turn right at an intersection on a left-hand traffic road. We experimentally investigated the drivers' gaze, vehicle speed, and distance on the vehicle traveling trajectory from the vehicle to the pedestrian crossing line, using a sedan and a truck with a gross vehicle weight of < 7.5 tons (a light-duty truck) during right-turn maneuver. We considered four different conditions: no pedestrian dummy (No-P), right pedestrian dummy (R-P), left pedestrian dummy (L-P), and right and left pedestrian dummies (RL-P). Regarding the gazing characteristics, there was no significant difference in the average total gaze time at each AOI between the two vehicles under different conditions, which suggests that the total gaze time was not affected by the vehicle type. All participants gazed at the pedestrian dummies in R-P, L-P, and RL-P. However, the average total gaze time at the right pedestrian dummy (0.63-0.72 s) in R-P was significantly shorter than that at the left pedestrian dummy (1.46-1.57 s) in L- P for both vehicles. The average vehicle speed at the entrance line to the intersection (L1) of the light-duty truck (16.8-18.2 km/h) was lower than that of the sedan (18.8-19.7 km/h). The average vehicle speed at the pedestrian crossing line (L0) of the light-duty truck (15.5-16.0 km/h) was lower than that of the sedan (16.0-17.8 km/h). There was no significant difference in the average vehicle speeds at L1 and L0 between them under any two conditions. We investigated the estimated time to collision (TTC), calculated from the distance on the vehicle traveling trajectory from the vehicle to the pedestrian crossing line and the vehicle speed at the moment when the drivers first gazed at the pedestrian dummies. The average TTC of the right pedestrian dummy in R-P for the sedan (3.5 s) was significantly shorter than that for the light-duty truck (4.0 s). Similarly, the average TTC of the left pedestrian dummy in L-P for the sedan (3.7 s) was significantly shorter than that for the light-duty truck (4.8 s). The driving characteristics obtained in this study may contribute to the development of advanced driver support systems, particularly for vehicles turning right at intersections.