ABSTRACT
Driver’s inattention to blind spots is one of the main causes of lane change-related car accidents. Efforts have been made to eliminate such blind spots but there still exist some areas around the vehicle that cannot be directly observed by the driver. Also, drivers cannot always focus on the rear-view mirror or side mirrors that help them to monitor other vehicles near blind spots. So, for this study, we used a collision warning system based on a different modality to find out whether it can enhance drivers’ awareness of other vehicles in blind spots. A haptic feedback was applied on a steering wheel for BSW (Blind Spot Warning). Haptic feedbacks are known to have several advantages over other modalities. First, they do not require any extra visual load which is already heavily placed upon drivers while driving in general cases. Second, haptic warnings are transmitted to the driver in a private way so other passengers are not disturbed by warnings like flashing lights or loud alarms. Third, haptic feedbacks are free from ambient noises that are generated by various sources around the driver. In this study, the effectiveness of haptic feedback was evaluated by comparing the performance and preference measures of the haptic condition with the non-haptic condition. For the performance measure, the collision prevention rate was analyzed as well as the minimum distance between the vehicles after collision events were carried out. As for the preference measure, the participants were asked to score the perceived usefulness and the overall satisfaction 410of the provided collision warning. For this experiment, a total number of twenty-four males in two different age groups (30-40 yrs and 50-60 yrs) were recruited to define the age effect. A virtual driving simulator with a software program and devices was developed and collision scenarios were provided to the participants. In the experimental scenario, participants were to perform as drivers and were asked to follow a preceding car which changes lanes from time to time. A haptic warning signal was presented on the steering wheel when a vehicle approached from the driver’s blind spot while the participant moved into the other lane to follow the preceding car. Haptic feedbacks were generated in separated locations (left and right) of the steering wheel corresponding to the direction of the possible collision event. The warning was provided to the participants 4 seconds before an expected collision. To isolate the vibration of each haptic feedback and prevent them transferring from one side to the other, the rim of the steering was sawed-off. As shown in the evaluation result, the effect of haptic BSW was valid to the participants. They avoided possible collision situations better with the help of haptic BSW. Also, when the participants successfully avoided the collision event, the mean minimum distance between their vehicle and the other vehicle increased, indicating the decreased possibilities of an accident. In terms of age, the younger group has shown better performance than the older group due to their superior detectability of haptic stimuli and motor skills. As for preference measures, the participants felt haptic BSWs as useful and were highly. The older participants in particular have shown higher level of perceived usefulness and satisfaction with haptic BSWs. From the result of our study, we conclude that the haptic BSW on a steering wheel could be helpful for safe driving.
