Assessment of a Driver Distraction Warning device in urban driving

In recent years, statistics indicate that distraction and drowsiness of drivers are the main causes of collision. In 2019, the European Parliament and the Council approved a law (Regulation (EU) 2019/2144) which indicates that by 2024 new vehicles must be equipped with the so-called advanced Driver Distraction Warning (DDW) device. This study aims at evaluating the effectiveness of a DDW device in an urban environment, with drivers operating in three different events: (i) interaction with a pedestrian at a mid-block crosswalk, (ii) driving in free-flow conditions, and (iii) interaction with a slow vehicle. Thirty participants, fifteen males and fifteen females, aged between 25 and 35, drove in three different distraction levels: (i) without distraction, (ii) with distraction and (iii) with distraction but supported by the DDW device. The distraction consisted in a secondary task, with drivers that had to respond to text messages on their own mobile phone. The experimental hypothesis is that the DDW device improves the driver’s behavior and contrasts the negative impact of distraction when performing the secondary task. The distraction level was considered as a within-subject factor, with the same person testing all the three conditions of distraction in a random order. Surrogate safety measures, e.g., minimum instantaneous time to collision (MTTC) and post encroachment time (PET), were considered to evaluate the driver response during the interaction with pedestrians. The longitudinal (i.e., speed and deceleration) and transversal (i.e., lateral position) driver behaviors were evaluated in the other two interactions. The headway was also considered as a surrogate measure in the case of the car following scenario. The Repeated Measures ANalysis Of VAriance (RM-ANOVA) was used to analyze the data and interpret the effect of the experimental factors. Results confirmed the negative effects of distraction on the driver's behavior, that was improved by the use of the DDW device. Although drivers judged the device annoying and useless during the driving session, it was proved that the MTTC in the pedestrian-vehicle interactions were higher, thus safer. During the distracting task, drivers tended to reduce their speed to mitigate risks. However, when supported by the DDW device, they adopted higher speeds. The effectiveness of the DDW device was also confirmed by the lateral behavior. Mean and standard deviation of lateral position were considerably higher when drivers were distracted without the support of the DDW device. Moreover, drivers were also induced in a better steering control when interacting with a slow vehicle in front.