Efficacy of haptic blind spot warnings applied through a steering wheel or a seatbelt

This study evaluates the efficacy of haptic feedback for the Blind Spot Warnings (BSWs) that are delivered to a driver through a steering wheel or a seatbelt. To this end, we developed a virtual driving simulator that implemented potential side collision scenarios. Haptic BSWs were issued as a vibrotactile alert during lane changes if a car in the target lane approached from the participant's blind spot at a faster speed. The two haptic warning types were assessed through a human factors experiment with participants of two age groups: younger (30-40 years) and older (50-60 years). No warning condition was also included as the control condition. As performance measures, the Collision Prevention Rate (CPR) and the Minimum Distance by which a collision was Avoided (MDA) were collected. As preference measures, the participants' perception of usefulness of the haptic warnings and their overall satisfaction were used. Experimental results showed that the highest CPR, the longest MDA, and the highest preference were achieved when BSWs were delivered through the steering wheel. For the seatbelt BSW, the CPR and MDA did not increase with statistical significance than those of the no-warning condition, but the participants felt that the haptic seatbelt was useful with high satisfaction. Interestingly, the scores of perceived usefulness and satisfaction were higher with the older group, suggesting that older drivers can be more willing to accept these new types of warning. In addition, the experiment suggested several factors that need to be studied to further improve the performance and preference of haptic BSW, such as warning issue timing and vibration intensity.