Mobile phone use while driving: Predicting drivers’ answering intentions and compensatory decisions

Abstract

The current study considered, for the first time, compensatory decisions within the theory of planned behaviour (TPB) to explain why people use mobile phones while driving. The effects of age, gender, and mobile phone mode on respondents’ answering intentions and compensatory decisions were mainly examined. A series of questions were administered to 333 drivers (ages 25–59), which included (1) demographic measures, (2) scales that measured prior mobile use activities in both driving and ordinary contexts, (3) a question to measure drivers’ perceptions of the safety of hands-free phones, and (4) TPB measures, which measured answer intention and two compensatory behavioural decisions (i.e., reminding the caller that he/she is driving, limiting the length of a conversations (including perceived its limits)), along with predictive variables. Drivers reported a moderate likelihood of answering intention and a strong tendency to engage in the two compensatory behaviours. Answering intention and compensatory decisions, perceived behavioural control, perceived risk, and usage frequency were more dependent on mobile phone mode and age group than gender. The regression models explained 64% and 67% of the variance in answering intention in the handheld and hands-free scenario separately. Attitudes, subjective norms, perceived behavioural risk and control (PBRC), and prior answering behaviour emerged as common predictors. The predictive models explained 31% and 37% of the variance for perceived limits of a conversation length in handheld and hands-free scenarios, respectively. Answering intention and PBRC consistently predicted most of the variance (handheld: 28%; hands-free: 32%) for this compensatory perception limits. The theoretical and practical implications of these results are discussed.

Introduction

Mobile phone use while driving is an important contributor to driver distraction, and a significant body of recent research has revealed that this behaviour can cause impairments in driving performance (e.g., Strayer and Johnston, 2001, Strayer et al., 2003, Gugerty et al., 2004, Rakauskas et al., 2004, Svenson and Patten, 2005, Horrey et al., 2008, Nasar et al., 2008, Backer-Grøndahl and Sagberg, 2011). Epidemiological and correlational studies suggest that this behaviour also increases the likelihood of serious driving accidents (e.g., Violanti and Marshall, 1996, Violanti, 1999, Lamble et al., 2002, Laberge-Nadeau et al., 2003, McEvoy et al., 2006). However, mobile phone use while driving represents a pervasive world-wide phenomenon, and a great number of drivers use their phones while driving. Given the safety implications of mobile phone use while driving and the scarcity of studies focusing on drivers’ intentions (especially with regard to the engagement in compensatory actions) (e.g., Walsh et al., 2008, Zhou et al., 2009b, White et al., 2010), this study aimed to consider drivers’ compensatory behavioural decisions within a modified structure of the theory of planned behaviour (TPB) to explore why people use mobile phones while driving.

Driver distraction can be defined as a diversion of attention away from activities critical for safe driving and towards a competing activity (Lee et al., 2008). Mobile phone use is considered to be a distracting activity; therefore, many countries (e.g., Australia, China, and Norway) have created legislation to restrict the use of handheld mobile phones while driving. A considerable number of studies have focused on the safety of mobile phone use while driving. Using methods such as simulation or field testing, a significant body of research confirms that both the handheld and hands-free modes of mobile phone use impair driving performance, even though the physical demands may be less for the hands-free mode than for the handheld mode (e.g., Haigney et al., 2000, Strayer and Johnston, 2001, Strayer et al., 2003, Gugerty et al., 2004, Rakauskas et al., 2004, Treffner and Barrett, 2004, Tornros and Bolling, 2005, Horrey and Wickens, 2006, Caird et al., 2008, Nasar et al., 2008). These studies suggest that regardless of the mode of mobile phone use, driving should always be the primary task, and the act of phoning while driving should always be specified as a secondary task. In this dual-task scenario, drivers may not have enough cognitive capacity to allocate to both talking and driving simultaneously, and driving performance suffers when mental resources are diverted in favour of the secondary task (e.g., Dressel and Atchley, 2008, Nelson et al., 2009). The cumulative results of these studies suggest that mobile phone use while driving has a significant negative effect on drivers’ cognitive distraction or performance for both the hands-free and handheld modes.

However, evidence from other studies addressing driver’s risk perception indicated that people perceived the behaviour of mobile phone use when driving to be safer and reported stronger intentions to use mobile phone in hands-free mode than in handheld mode (e.g., White et al., 2004, Zhou et al., 2009b, Backer-Grøndahl and Sagberg, 2011). Public opinion surveys reflect these results. For example, in China, 65.3% of internet respondents perceived a higher risk for the handheld mode than for the hands-free mode, and only 25% of them thought that the use of hands-free kits had the same risk level as handheld sets when driving (CCTV and Sina, 2006). In the UK, two public surveys found that 88% of people are in favour of regulating the use of handheld sets, whereas public opinion seems far more ambivalent about the use of hands-free kits, with only 45% calling for similar regulation (see White et al., 2004). In Finland, over 75% of survey respondents believed that the government should ban the use of handheld mobile phones while driving, but only 27% believed that hands-free mobile phone use should be banned while driving (Lamble et al., 2002). However, the majority of people still tend to use handheld sets. For example, a survey conducted in a sample group of Spanish university workers indicated that only 14.3% of respondents who use a mobile phone while driving use a hands-free device (Gras et al., 2007), and a survey of Austrian citizens suggested that 63.9% of drivers did not own hands-free kits and that, of the drivers who did own hands-free kits, 32% did not use those kits most or all of the time (White et al., 2010). Therefore, when examining drivers’ attitudes and motivations to use mobile phones while driving, the type of mobile phone (handheld or hands-free) should be considered an important variable. Drivers’ differing responses based on cell phone mode should be stressed in tandem with their risk perception of this behaviour.

Some studies, using either self-report or observational methods, have focused on drivers’ perceived risk of mobile phone use while driving. Generally, people ranked mobile phone use as riskier in a driving context than in other ordinary situations (Zhou et al., 2009b). A recent study conducted by Backer-Grøndahl and Sagberg (2011) asked drivers to rate the perceived degree of risk for 23 distracting activities and other risky behaviours. Sending text messages, reading, and writing were perceived to be the most dangerous of the distracting activities. An earlier study (Smith, 1978) also found that reading a map and writing something down were perceived to be the riskiest activities for drivers. The results of these perceived risk studies were consistent with those of some current studies asking drivers’ about their engagement in distracting activities. These current studies suggest that the order of frequency for intended mobile phone activities when driving is (1) answering calls, (2) making calls, (3) reading text messages, and (4) sending text messages (Walsh et al., 2008, Zhou et al., 2009b, White et al., 2010).

Driver demographic characteristics are also considered to be important factors moderating drivers’ engagement in mobile phone use while driving. Some studies have examined the impact of age and gender on drivers’ mobile phone use and on the perceived risk of this behaviour. Evidence indicates that younger drivers tend to use mobile phones while driving more often than older drivers. For example, a survey by Backer-Grøndahl and Sagberg (2011) found that only 27.8% of older drivers (55+ years) reported using a mobile phone while driving, compared to 69.8% of middle-aged drivers (aged 26–54 years) and 69.6% of young drivers (aged 18–25 years). Other studies (Lamble et al., 2002, Brusque and Alauzet, 2008) also found that young drivers reported a much higher level of mobile phone use while driving than did older drivers. When examined in combination with gender, research shows that the youngest drivers and males use their phones while driving more often than older drivers and females (Brusque and Alauzet, 2008) and that females are almost twice as likely to restrict mobile phone use than males (Lamble et al., 2002). Zhou et al.’s study (2009b) indicated that males learning to drive reported relatively stronger perceived behavioural control for using a mobile phone when driving than females. Moreover, these two individual factors also influenced the drivers’ perceived risk of mobile phone use while driving. Two surveys conducted in Australia indicated that young drivers rated most items on a list of distracting and risky activities (e.g., dialling, answering and talking on a mobile phone while driving) as less dangerous than the older drivers rated them (i.e., McEvoy et al., 2006, Backer-Grøndahl and Sagberg, 2011). Male drivers rated some activities, such as answering a mobile phone while driving, as less dangerous than the females rated them (Backer-Grøndahl and Sagberg, 2011).

Overall, the collective results of these studies suggest that the use of mobile phones is pervasive around the world, and people’s risk perception of this behaviour varies on different situations or variables. It is therefore important to focus on explaining drivers’ motivations and decision-making processes in addition to factors such as perceived risk, gender, age, and modes of mobile phone use.

As a complete model for explaining social behaviour, the theory of planned behaviour (TPB; Ajzen, 1991) can be applied to address the issue of people’s decisions to use mobile phones while driving. According to the TPB, behavioural intentions are immediate predictors of behaviour and are influenced by attitudes towards the behaviour, subjective norms, and perceived behavioural control (Ajzen, 1991). Behavioural intention reflects the motivation to perform the behaviour and the likelihood with which respondents will perform it in the future. Attitudes are personal beliefs about the potential outcomes of the behaviour, including either positive or negative evaluations of these outcomes. Subjective norms reflect personal beliefs about the normative expectations of others and the motivation to comply with these expectations. Perceived behavioural control (PBC) refers to beliefs about one’s ability to perform (or not to perform) the behaviour, which has direct effects on behaviour.

In a wide variety of behavioural domains, including road safety, a number of studies have used the TPB to account for drivers’ intentions to obey the speed limit (e.g., Elliott et al., 2003, Elliott et al., 2005, Elliott et al., 2007, Newnam et al., 2004, Paris and Broucke, 2008, Forward, 2009, Cestac et al., 2011) and commit driving violations (e.g., Parker et al., 1992, Díaz, 2002, Poulter et al., 2008, Forward, 2009), passengers’ seat belt use intentions (Şimşekoğlu and Lajunen, 2008), and pedestrians’ road crossing intentions (e.g., Evans and Norman, 1998, Evans and Norman, 2003, Holland and Hill, 2007, Zhou et al., 2009a, Zhou and Horrey, 2010). The TPB has also been successfully employed to address drivers’ mobile phone use intentions while driving (Walsh et al., 2008, Zhou et al., 2009b). Zhou et al. (2009b) investigated young student drivers’ (aged from 17 to 34 years) intentions to use a mobile phone when driving. The results of the study indicated that the TPB variables (attitude, subjective norm, and perceived behavioural control) were able to explain the relatively large (43% and 48%) variance for hands-free and handheld mobile phone use intentions, respectively, with perceived behavioural control emerging as the strongest predictor. Walsh et al. (2008) used the TPB framework to examine predictors (i.e., attitudes, norms, control factors, and risk perceptions) of drivers’ (aged from 17 to 76 years) intentions to use a mobile phone while driving in general, as well as for calling (defined as making or answering a call) and text messaging (defined as sending or reading a text message), in four scenarios differing in descriptions of vehicle speed and time pressure (i.e., 100 km/h, running late; 100 km/h, not in a hurry; waiting at traffic lights, running late; and waiting at traffic lights, not in a hurry). The results indicated that attitude, subjective norms, and PBC accounted for 32–39% of the variance for general and calling intentions, with attitude identified as the strongest predictor. Less support was found for the predictive ability of subjective norms and PBC on text messaging intention, although the models in the four situations accounted for 11–14% of the variance in these scenarios. Overall, the results from these two studies (Walsh et al., 2008, Zhou et al., 2009b) support the validity of the TPB and indicate that in addition to the standard TPB components of attitude, subjective norm, and PBC, extended variables such as individual factors (e.g., gender and age), driving purpose, crash risk, and risk apprehension are also possible predictors of intentions to use a mobile phone when driving.

The previous literature suggests that many drivers continue to use handheld devices and that they believe the use of hands-free mobile phones is safer while driving (e.g., Zhou et al., 2009b). Mobile phone use in conjunction with more physical demands, such as using a handheld set, making a call, and sending a short message, tends to be perceived as riskier. Drivers tend to give low ratings when asked of their intentions to use a phone while driving. However, there is increasing evidence of widespread actual mobile use while driving. This leads to a question: When a driver knows that using a mobile phone while driving is risky, but he/she needs to use a mobile phone while driving, how does he/she modulate his/her behaviour accordingly?

To answer this question, it may be important to know whether and how drivers self-regulate their driving to compensate for the impairment caused by phone use. With more research now documenting the effect of mobile phone use on driving safety, some recent attention has been given to the possible compensatory behaviours involved in mobile use while driving, including stopping the vehicle (e.g., Gras et al., 2007), reducing the speed (e.g., Haigney et al., 2000, Rakauskas et al., 2004), and increasing the following distance (e.g., Alm and Nilsson, 1995, Strayer et al., 2003, Strayer et al., 2006, Strayer and Drews, 2004). However, evidence from studies exploring whether drivers adopt these behaviours to compensate for driving performance decrements during cell phone is complicated, and the major of the research does not show compensation or its opposite (Haigney et al., 2000, Caird et al., 2008, Rosenblatt and Li, 2010). Some findings indicate that drivers may engage in such compensatory action to offset perceived risk when using a cell phone. For example, drivers may reduce their speed and increase their following distance in response to changing or competing task demands to maintain an adequate level of safe driving (Haigney et al., 2000, Rakauskas et al., 2004, Strayer and Drews, 2004). The driver’s a priori confidence in his/her ability to deal with distracters (i.e., cell-phone use) may impact decisions to engage in compensatory behaviours (Lesch and Hancock, 2004). Drivers may compensate for the deleterious effects of cell phone use by decreasing their speed when using a handheld phone but neglect to do so when using a hands-free phone (e.g., Ishigami and Klein, 2009). However, some researchers have not found evidence of driver compensation. For example, drivers did not compensate for impairment during cell phone conversations by increasing headway or decreasing their speed during the phone task (Alm and Nilsson, 1995, Rosenbloom, 2006). And drivers using either phone type (i.e., handheld or hands-free mobile phone) do not appreciably compensate by increasing following distance or reducing speed (e.g., Caird et al., 2008).

Most commonly, pulling over to the side of the road, increasing following distance, and stopping the vehicle were reported as compensatory actions by the major of drivers when they engaged in distracting activities such as mobile phone use Young and Lenné (2010). However, other compensatory behaviours that are more directly related to mobile phone use (such as shortening the conversation time while on a mobile phone and reminding the caller that he/she is currently driving) were not considered in previous studies. Therefore, to understand the relationship between drivers’ confidence in driving ability, risk perception, mobile phone activities and compensatory behaviours, it is important to find a suitable way to predict drivers’ decisions regarding compensatory behaviours.

In psychology, human behaviour is often used to illustrate an individual’s observable responses in a given situation with respect to a given target. Usually, human actions are related. Compensatory behaviour is created because of a primary behaviour; it occurs in response to the primary action. Correspondingly, an individual’s intention to perform a compensatory behaviour can be called compensatory behavioural intention or decision. How does one predict compensatory behavioural intention? We can use the TPB and design specific scenarios to investigate these decisions. Using this method, however, makes it difficult to find the relationship between mobile phone use intention and a driver’s compensatory decisions. According to the TPB (Ajzen, 1991), a behaviour is a function of behavioural intentions and perceived behavioural control. Additionally, according to a previous study (e.g., Lesch and Hancock, 2004), drivers’ decisions to engage in compensatory behaviours are impacted by their confidence in the ability or perceived behavioural control toward mobile phone use while driving. Considering this finding, we present a modified TPB model (see Fig. 1), which assumes that behavioural intentions are an indication of an individual’s potential compensatory behavioural decisions and that perceived behavioural control will moderate the effect of behavioural intentions on compensatory decisions. For example, in the context of driving, driving safely is a primary action, mobile phone use is a secondary task, and behaviour such as reducing mobile phone use is a compensatory action. Therefore, from the perspective of the driver, compensatory behaviour is enacted to maintain a balance between driving safely and using a mobile phone. According to the TPB, behavioural intention is assumed to be an immediate antecedent of behaviour (Ajzen, 1991). The intentions to remind a caller of one’s driving status and to limit mobile conversation time (including perceived limits of a conversation length) were selected as compensatory decisions in the study.

To date, few studies have focused on predicting compensatory decisions in the context of driving. The current study seeks for the first time to consider compensatory decisions within a modified TPB framework to explain why people use mobile phones while driving. In this study, we extend the findings from Zhou et al.’s study (2009b) to another driver population. Whereas Zhou and colleagues focused on students in driving schools, the current study uses a sample of licensed drivers with at least 1 year of driving experience to increase external validity and practical significance. Another change that we made was to use indirect belief-based scales to measure respondents’ attitudes and subjective norms. Specifically, we tried to use the modified TPB model as presented in Fig. 1 to examine how different demographic characteristics influence (1) a driver’s decision to answer a call and (2) a driver’s compensatory intentions to deal with the call, in both handheld and hands-free scenarios. In this study, we define answering a call as the main behavioural intention, and we define reminding the caller that one is driving and limiting the length of the conversation (including perceived limits of a conversation length) as compensatory behavioural decisions or intentions. We expect that these decisions will have a direct relationship with the control of mobile phone use while driving.

Thus, the main goals of this study were to:

• Examine the effects of age and gender on behavioural intentions (including answering intention and compensatory intentions) in scenarios that include either handheld sets or hands-free kits.

• Investigate whether age, gender or situation (handheld vs. hands-free scenario; driving vs. ordinary life context) affects drivers’ perceived behavioural control, perceived risk, or mobile phone use activities.

• Address the extent to which the answering intentions of drivers can be predicted by the TPB variables (i.e., attitude, subjective norm, perceived behavioural control, and prior answering behaviour), gender, age, and prior use behaviour.

• For the first time, address whether compensatory decisions to use mobile phone while driving can be predicted by a modified TPB model with predictors of the answering intention and other elements of the TPB, in particular PBC.