JMIR Publications

ABSTRACT

Background:

Investigating ways to improve well-being in everyday situations as a means of fostering mental health has gained substantial interest in recent years. For many people, the daily commute by car is a particularly straining situation of the day, and thus researchers have already designed various in-vehicle well-being interventions for a better commuting experience. Current research has validated these interventions but there remains a lack of knowledge about when drivers are in a state of vulnerability. By identifying these situations, interventions could be effectively delivered to increase well-being.

Objective:

The aim of the study was to identify cause-effect relationships between driving behavior and well-being in a real-world setting. This knowledge should contribute to a better understanding of when to trigger interventions.

Methods:

We conducted a field study in which we provided ten commuters with a car for daily driving. Each driver had to fill out a questionnaire about their state of well-being before and after driving. Well-being was operationalized as arousal and valence. We equipped the cars with sensors that recorded driving behavior such as sudden braking. We also captured trip-dependent factors such as the length of the drive, and pre-determined factors such as the weather. We conducted a causal analysis based on causal directed acyclic graphs to examine cause-effect relationships from the observational data and to isolate the causal chains between the examined variables. We did so by applying the backdoor criterion on the graphical model, which was learned from the data. The hereby compiled adjustment set was used in a multiple regression to estimate the causal effects between the variables.

Results:

The causal analysis showed that a higher level of arousal before driving had an impact on driving. It reduced the frequency of sudden events (P = 0.035) as well as the average speed (P = 0.001) while fostering active steering (P < 0.001). In turn, more frequent braking (P < 0.001) increased arousal after the drive, while a longer trip (P < 0.001) with a higher average speed (P < 0.001) reduced arousal. The prevalence of sunshine (P < 0.001) increased arousal and of occupants (P < 0.001) increased valence (P < 0.001) before and after driving.

Conclusions:

The examination of cause-effect relationships unveiled significant interactions between well-being and driving. A low level of pre-driving arousal impairs driving behavior, which manifests itself in more frequent sudden events and less anticipatory driving. Driving has a stronger effect on arousal than on valence. In particular, monotonous driving situations at high speeds with low cognitive demand increase the risk of the driver becoming tired (low arousal) and thus impairing driving behavior. By combining the identified causal chains, states of vulnerability can be inferred that may form the basis for timely delivered interventions to improve well-being while driving.