# An Analysis of Vulnerable Road Users Overtaking Maneuver along the Urban Road
###### Abstract  
This paper discusses driving styles while overtaking a vulnerable road user who moves along the shoulder in urban roads. Based on the data obtained from an experiment in pre-defined conditions (combinations of four main effects: vehicle's initial speed, lane width of the road, vulnerable road users' type, and location in the shoulder) with an immersive driving simulator, we analyzed four different driving styles of drivers while approaching and passing the objects. It is shown that drivers took avoidance maneuvers even if there was no clear risk of collision to vulnerable road users. The results showed that the drivers tended to have a unique perception about the lateral passing gap and overtaking strategy with two worth notice groups: overcavation drivers and reckless drivers. The road characteristic has a statistically significant effect for all types of drivers. Moreover, the effect of the vehicle's initial speed on overtaking strategy and the effect of vulnerable road user location on minimum lateral passing gap are statistically significant. The findings provide some implications for the development of automotive safety systems that can reduce the risk of overtaking maneuvers in urban areas. m 2021 2021 5 July 2021 9 July 2  
the avoidance; (3) vehicle passes the object and (4) vehicle returns to its own lane [2]. In the approaching phase, drivers have dissimilar behaviors to regulate speed before making overtaking decisions. Two strategies of overtaking were suggested: flying overtaking (in which drivers prefer to keep higher speed in the approaching phase than initial speed), and accelerative overtaking (drivers reduce speed in the approaching phase) [10]. The ratio of the vehicle's minimum speed while approaching VRU to initial speed (RMS) can be used as a metric to distinguish these strategies. For VRU overtaking, the flying overtaking maneuver (RMS is about 1) was not preferred and drivers chose to decelerate to a speed that was lower than the initial speed [11] and RMS is much lower than 1. A variety of safety metrics has been proposed: minimum distance from the vehicle to object in approaching, steering, passing, returning phase of an overtaking (Comfort Zone Boundary), time to a collision between motorist and VRU or incoming vehicle, vehicle speed at specific timing [2; 5; 12; 13; 14; 15; 16; 17]. Above all, the minimum lateral gap while passing objects (LPG) is definitely a key metric for safety [2]. LPG is influenced by the driver [16], so classification of driver behavior may provide useful information. Bicycle passing laws (1.5 m in a rural road in some European countries [4]) could influence drivers' habits. Larger lane width could lead to greater LPG as the driver will be less constrained by oncoming or adjacent motor vehicles [12]. Higher vehicle velocity should lead to larger LPG as it reduces time to collision and may cause higher accident risk [12]. LPG also had been found larger in accelerative maneuvers than in flying maneuvers [14]. Overall, LPG and RMS are important indicators for driver behavior in overtaking maneuvers. These indicators are greatly influenced by road configuration, vehicle speed on rural roads. Hence, the influences of urban's infrastructure (fixed lane width, shoulder width with a variation of speed limit) on these indicators are on demand. On the other side, no study has classified driver behavior to rate, train drivers, and provide a guideline in designing safety systems. It is worth noting that safety system warnings and intervention must be accepted by drivers or they won't be put into action [13]. To simplify the prediction of driver's acceptance, we proposed that there are divergent groups of drivers. In our experiment, the drivers drove normally in a normal state without other attractions (using a smartphone... other road users). Using influential indicators (LPG, RMS) to investigate the driver behavior, we aim to prove the non-identical behavior even in undemanding situations, that must be considered when developing the safety systems.