Effects of naturalistic cell phone conversations on driving performance

PROBLEM: The prevalence of automobile drivers talking on cell phones is growing, but the effect of that behavior on driving performance is unclear. Also unclear is the relationship between the difficulty level of a phone conversation and the resulting distraction. METHOD: This study used a driving simulator to determine the effect that easy and difficult cell phone conversations have on driving performance. RESULTS: Cell phone use caused participants to have higher variation in accelerator pedal position, drive more slowly with more variation in speed, and report a higher level of workload regardless of conversation difficulty level. CONCLUSIONS: Drivers may cope with the additional stress of phone conversations by enduring higher workloads or setting reduced performance goals. IMPACT ON INDUSTRY: Because an increasing number of people talk on the phone while driving, crashes caused by distracted drivers using cell phones will cause disruptions in business, as well as injury, disability, and permanent loss of personnel.     

Cell phones and driving: review of research

OBJECTIVE: The research literature on drivers' use of cell phones was reviewed to identify trends in drivers' phone use and to determine the state of knowledge about the safety consequences of such use. METHODS: Approximately 125 studies were reviewed with regard to the research questions, type and rigor of the methods, and findings. Reviewed studies included surveys of drivers, experiments, naturalistic studies (continuous recording of everyday driving by drivers in instrumented vehicles), studies of crash risk, and evaluations of laws limiting drivers' phone use. RESULTS: Observational surveys indicate drivers commonly use cell phones and that such use is increasing. Drivers report they usually use hand-held phones. Experimental studies have found that simulated or instrumented driving tasks, or driving while being observed, are compromised by tasks intended to replicate phone conversations, whether using hand-held or hands-free phones, and may be further compromised by the physical distraction of handling phones. Effects of phone use on driving performance when drivers are in their own vehicles are unknown. With representative samples of adequate size, naturalistic studies in the future may provide the means to document the patterns and circumstances of drivers' phone use and their effects on real-world driving. Currently, the best studies of crash risk used cell phone company billing records to verify phone use by crash-involved drivers. Two such studies found a fourfold increase in the risk of a property-damage-only crash and the risk of an injury crash associated with phone use; increased risk was similar for males and females, younger and older drivers, and hands-free and hand-held phones. A number of jurisdictions in the United States and around the world have made it illegal for drivers to use hand-held phones. Studies of these laws show only limited compliance and unclear effects on safety.CONCLUSIONS: Even if total compliance with bans on drivers' hand-held cell phone use can be achieved, crash risk will remain to the extent that drivers continue to use or switch to hands-free phones. Although the enactment of laws limiting drivers' use of all phones is consistent with research findings, it is unclear how such laws could be enforced. At least in the short term, it appears that drivers' phone use will continue to increase, despite the growing evidence of the risk it creates. More effective countermeasures are needed but are not known at this time.     

The relationship between cell phone use and management of driver fatigue: It's complicated

Introduction: Voice communication may enhance performance during monotonous, potentially fatiguing driving conditions (Atchley & Chan, 2011); however, it is unclear whether safety benefits of conversation are outweighed by costs. The present study tested whether personalized conversations intended to simulate hands-free cell phone conversation may counter objective and subjective fatigue effects elicited by vehicle automation. Method: A passive fatigue state (Desmond & Hancock, 2001), characterized by disengagement from the task, was induced using full vehicle automation prior to drivers resuming full control over the driving simulator. A conversation was initiated shortly after reversion to manual control. During the conversation an emergency event occurred. Results: The fatigue manipulation produced greater task disengagement and slower response to the emergency event, relative to a control condition. Conversation did not mitigate passive fatigue effects; rather, it added worry about matters unrelated to the driving task. Conversation moderately improved vehicle control, as measured by SDLP, but it failed to counter fatigue-induced slowing of braking in response to an emergency event. Finally, conversation appeared to have a hidden danger in that it reduced drivers' insights into performance impairments when in a state of passive fatigue. Conclusions: Automation induced passive fatigue, indicated by loss of task engagement; yet, simulated cell phone conversation did not counter the subjective automation-induced fatigue. Conversation also failed to counter objective loss of performance (slower braking speed) resulting from automation. Cell phone conversation in passive fatigue states may impair drivers' awareness of their performance deficits. Practical applications: Results suggest that conversation, even using a hands-free device, may not be a safe way to reduce fatigue and increase alertness during transitions from automated to manual vehicle control.     

Self-regulation of driving speed among distracted drivers: An application of driver behavioral adaptation theory

Objective: The adaptive behavior of mobile phone–distracted drivers has been a topic of much discussion in the recent literature. Both simulator and naturalistic studies suggest that distracted drivers generally select lower driving speeds; however, speed adaptation is not observed among all drivers, and the mechanisms of speed selection are not well understood. The aim of this research was to apply a driver behavioral adaptation model to investigate the speed adaptation of mobile phone–distracted drivers.

Methods: The speed selection behavior of drivers was observed in 3 phone conditions including baseline (no conversation) and hands-free and handheld phone conversations in a high-fidelity driving simulator. Speed adaptation in each phone condition was modeled as a function of secondary task demand and self-reported personal/psychological characteristics with a system of seemingly unrelated equations (SURE) accounting for potential correlations due to repeated measures experiment design.

Results: Speed adaptation is similar between hands-free and handheld phone conditions, but the predictors of speed adaptation vary across the phone conditions. Though perceived workload of secondary task demand, self-efficacy, attitude toward safety, and driver demographics were significant predictors of speed adaptation in the handheld condition, drivers' familiarity with the hands-free interface, attitude toward safety, and sensation seeking were significant predictors in the hands-free condition. Drivers who reported more positive safety attitudes selected lower driving speeds while using phones.

Conclusion: This research confirmed that behavioral adaptation models are suitable for explaining speed adaptation of mobile phone distracted drivers, and future research could be focused on further theoretical refinement.     

Examination of drivers' cell phone use behavior at intersections by using naturalistic driving data

IntroductionMany driving simulator studies have shown that cell phone use while driving greatly degraded driving performance. In terms of safety analysis, many factors including drivers, vehicles, and driving situations need to be considered. Controlled or simulated studies cannot always account for the full effects of these factors, especially situational factors such as road condition, traffic density, and weather and lighting conditions. Naturalistic driving by its nature provides a natural and realistic way to examine drivers' behaviors and associated factors for cell phone use while driving.MethodIn this study, driving speed while using a cell phone (conversation or visual/manual tasks) was compared to two baselines (baseline 1: normal driving condition, which only excludes driving while using a cell phone, baseline 2: driving-only condition, which excludes all types of secondary tasks) when traversing an intersection.ResultsThe outcomes showed that drivers drove slower when using a cell for both conversation and visual/manual (VM) tasks compared to baseline conditions. With regard to cell phone conversations, drivers were more likely to drive faster during the day time compared to night time driving and drive slower under moderate traffic compared to under sparse traffic situations. With regard to VM tasks, there was a significant interaction between traffic and cell phone use conditions. The maximum speed with VM tasks was significantly lower than that with baseline conditions under sparse traffic conditions. In contrast, the maximum speed with VM tasks was slightly higher than that with baseline driving under dense traffic situations.Practical applicationsThis suggests that drivers might self-regulate their behavior based on the driving situations and demand for secondary tasks, which could provide insights on driver distraction guidelines. With the rapid development of in-vehicle technology, the findings in this research could lead the improvement of human-machine interface (HMI) design as well.     

Cell phone users, reported crash risk, unsafe driving behaviors and dispositions: a survey of motorists in Maryland

INTRODUCTION: The purpose of this investigation was to identify risky driving behaviors and dispositions that distinguish drivers who use a cell phone while operating a motor vehicle from non-cell phone using drivers. METHOD: Annual telephone surveys were used to identify drivers who reported using a cell phone while driving in the last month (n=1803) and were compared to those who said they did not use cell phones while driving (n=1578). RESULTS: Cell phone using drivers were more likely to report driving while drowsy, going 20 mph over the speed limit, driving aggressively, running a stop sign or red light, and driving after having had several drinks. They were also more likely to have had a prior history of citation and crash involvement than non-cell phone using drivers. Cell phone using drivers also reported they were less careful and more in a hurry when they drive than non-cell phone using drivers. CONCLUSION: Cell phone using drivers report engaging in many behaviors that place them at risk for a traffic crash, independent of the specific driving impairments that cell phone usage may produce. Strategies that combine coordinated and sustained enforcement activities along with widespread public awareness campaigns hold promise as effective countermeasures for these drivers, who resemble aggressive drivers in many respects.     

Prevalence and trends of distracted driving in Canada

Introduction: This study evaluates prevalence and trends in distracted driving in Canada based on multiple indicators collected from the Road Safety Monitor (RSM) and Canada’s National Fatality Database maintained by the Traffic Injury Research Foundation (TIRF). Method: Data from the RSM on self-reported distracted driving behaviors were analyzed using multivariate techniques including logistic regression analysis in various years spanning from 2004 to 2019. Data from TIRF’s National Fatality Database from 2000 to 2016 were also analyzed using piecewise regression analysis to evaluate trends and prevalence of driver distraction. Results: Significantly more Canadians reported talking on their phone hands-free or handheld phone while driving in 2019 compared to 2010. There was a 102% increase in the percentage that reported texting while driving in 2019 (9.7%) compared to 2010 (4.8%). For every 10-year increase in age, drivers were 44% less likely to text, 38% less likely to use a handheld phone, and 28% less likely to use a hands-free phone. Males were 62% more likely to use a handheld phone and 50% more likely to use a hands-free phone than females. Findings related to drivers’ perceived danger of distracted driving and attitudes are also presented. Although the number of distraction-related fatalities has not increased substantially from 2000 to 2016, the percentage of all fatalities where distraction was a contributing factor has increased. Unlike drinking drivers, distracted drivers more often kill other road users in crashes than kill themselves. Conclusions: In conclusion, while most Canadians appear to understand that one of the high-risk forms of distracted driving (i.e., texting while driving) is indeed dangerous, there is a minority who are unaware of, or resistant to, this fact. Practical Applications: Enforcement activities and education initiatives to combat distracted driving ought to be tailored to the target audience based on the patterns uncovered.     

Drivers' visual behavior when using handheld and hands-free cell phones

ObjectiveThis study investigated driver distraction and how the use of handheld (HH), portable hands-free (PHF), and integrated hands-free (IHF) cell phones affected the visual behavior of motor vehicle drivers.MethodA naturalistic driving study recorded 204 participating drivers using video cameras and vehicle sensors for an average of 31 days. A total of 1564 cell phone calls made and 844 text messages sent while driving were sampled and underwent a video review. Baselines were established by recording epochs prior to the cell phone interactions. Total eyes-off-road time (TEORT) was examined to assess the visual demands of cell phone subtasks while driving. Percent TEORT was reported and compared against the baseline.ResultsVisual-manual subtasks performed on HH, PHF, and IHF cell phones were found to significantly increase drivers' mean percent TEORT. In contrast, conversing on an HH cell phone was found to significantly decrease drivers' mean percent TEORT, indicating that drivers looked at the forward roadway more often. No significant differences in percent TEORT were found for drivers conversing using PHF or IHF cell phones. The mean TEORT durations for visual-manual subtasks performed on an HH cell phone were significantly longer than the mean TEORT durations on either IHF or PHF cell phones.Practical applicationsThis research helps to further reinforce the distinction made between handheld and hands-free cell phone use in transportation distraction policy.     

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

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.     

Distracted walking: cell phones increase injury risk for college pedestrians

Introduction

Distraction on cell phones jeopardizes motor-vehicle driver safety, but few studies examine distracted walking. At particular risk are college students, who walk frequently in and near traffic, have increased pedestrian injury rates compared to other age groups, and frequently use cell phones. Method: Using an interactive and immersive virtual environment, two experiments studied the effect of cell phone conversation on distraction of college student pedestrians. In the first, we examined whether pedestrians would display riskier behavior when distracted by a naturalistic cell phone conversation than when undistracted. We also considered whether individual difference factors would moderate the effect of the distraction. In a second experiment, we examined the impact of three forms of distraction on pedestrian safety: (a) engaging in a cell phone conversation, (b) engaging in a cognitively challenging spatial task by phone, and (c) engaging in a cognitively challenging mental arithmetic task by phone. Results: Results revealed that cell phone conversations distracted college pedestrians considerably across all pedestrian safety variables measured, with just one exception. Attention to traffic was not affected by the naturalistic phone conversation in Experiment 1, but was altered by the cognitively-demanding content of some types of conversation in Experiment 2. The content of the conversation did not play a major role in distraction across other variables; both mundane and cognitively complex conversations distracted participants. Moreover, no significant associations between individual difference factors and susceptibility to distraction emerged. Impact on Industry: Results may inform researchers, policy makers, and pedestrians themselves. Educational campaigns might discourage telephone conversations in pedestrian environments.     

Is a hands-free phone safer than a handheld phone?

Introduction

Although it is becoming more and more accepted that driving while talking on a cell phone can be hazardous, most jurisdictions are making handheld phone use illegal while allowing hands-free phone use.

Methods

The scientific literature exploring the effects of these two types of cell phone use on driving and driving-related performance is reviewed here.

Results

Our review shows that talking on the phone, regardless of phone type, has negative impacts on performance especially in detecting and identifying events. Performance while using a hands-free phone was rarely found to be better than when using a handheld phone. Some studies found that drivers compensate for the deleterious effects of cell phone use when using a handheld phone but neglect to do so when using a hands-free phone.

Impact on Industry

Current research does not support the decision to allow hands-free phone use while driving.     

Tracing the physiological response and behavioral performance of drivers at different levels of mental workload using driving simulators

Introduction: The use of mobile phones while driving is known to be a distraction factor and a cause of accidents. The way in which different kinds of conversations affect the behavioral performance of the driver as well as the persistence of the effects are not yet fully understood. Method: In this study, in addition to comparing brain function and behavioral function in dual task conditions in three conversations types, the persistent effects of these types of conversations have also been traced. Results: The results show that the content of the mobile phone conversation while driving is the cause of the persistent changes in behavioral and brain functions. Increased time headway and lane departure was observed during and up to 5 min after the emotional conversation was finished. EEG bands also varied in different types of conversations. Cognitive conversations caused an increase in the activity of the alpha and beta bands while emotional conversations enhanced the rate of gamma and beta bands. A meaningful correlation was found between changes in the theta and alpha bands and changes in behavioral performance both during the dual task condition and after the conversation was finished, was also observed. Conclusions: The content of the conversation is one of the most important factors that increase the risk of road accidents. This can also deteriorate the behavioral performance of the driver and can have persistent effects on behavioral performance and the brain. Practical applications: The findings of this study provide a basis to measure and tracing drivers’ cognitive distractions induced by different levels of mental workload through physiological and behavioral performances.     

Driver hand-held cellular phone use: a four-year analysis

INTRODUCTION: The use of hand-held cellular (mobile) phones while driving has stirred more debate, passion, and research than perhaps any other traffic safety issue in the past several years. There is ample research showing that the use of either hand-held or hands-free cellular phones can lead to unsafe driving patterns. Whether or not these performance deficits increase the risk of crash is difficult to establish, but recent studies are beginning to suggest that cellular phone use elevates crash risk. METHODS: The purpose of this study was to assess changes in the rate of hand-held cellular phone use by motor-vehicle drivers on a statewide level in Michigan. This study presents the results of 13 statewide surveys of cellular phone use over a 4-year period. Hand-held cellular phone use data were collected through direct observation while vehicles were stopped at intersections and freeway exit ramps. Data were weighted to be representative of all drivers traveling during daylight hours in Michigan. RESULTS: The study found that driver hand-held cellular phone use has more than doubled between 2001 and 2005, from 2.7% to 5.8%. This change represents an average increase of 0.78 percentage points per year. The 5.8% use rate observed in 2005 means that at any given daylight hour, around 36,550 drivers were conversing on cellular phones while driving on Michigan roadways. The trend line fitted to these data predicts that by the year 2010, driver hand-held cellular phone use will be around 8.6%, or 55,000 drivers at any given daylight hour. CONCLUSIONS: These results make it clear that cellular phone use while driving will continue to be an important traffic safety issue, and highlight the importance of continued attempts to generate new ways of alleviating this potential hazard.     

Longer-term effects of Washington, DC, law on drivers' hand-held cell phone use

OBJECTIVES: To determine whether the substantial short-term declines in drivers' use of hand-held phones achieved in the District of Columbia (DC) were sustained 1 year after a ban. METHODS: Drivers' daytime hand-held cell phone use was observed in DC and nearby areas of Virginia and Maryland, states without bans. Observations were conducted several months before the ban, shortly after, and 1 year later. The number of vehicles observed in all three surveys combined was 51,945 in DC, 36,796 in Maryland, and 43,033 in Virginia. RESULTS: The rate of talking on hand-held phones declined significantly from 6.1 percent before the law to 3.5 percent shortly after; when measured 1 year later, use was 4.0 percent, still significantly lower than baseline. Based on increases in rates of talking on hand-held phones in Maryland and Virginia, longer-term phone use in DC was estimated to be 53 percent lower than would have been expected without the ban. Declines in DC were identified for drivers of vehicles registered in all three jurisdictions. CONCLUSIONS: In DC, there was an initial decline of about 50 percent in drivers talking on hand-held cell phones following a ban, and this decline was sustained about 1 year later. After a similar ban in New York, there was an initial decline in phone use comparable with the initial decline in DC, but the decline a year after the New York ban took full effect was only about 21 percent and not statistically significant. The potential difference in sustained effectiveness for the DC ban may reflect tougher enforcement in DC. Even if full compliance with hand-held phone bans can be achieved, the risks from drivers' use of hands-free phones will remain.     

In-car cell phone use and hazards following hands free legislation

OBJECTIVE: A new law took effect in Finland at the beginning of 2003 which prohibits the handheld use of mobile phones while driving a motor vehicle. The purpose of this study was to assess the impact of the law on phone usage and self-reported safety during the first few months and 16 months later to determine whether the initial level of compliance with the law had been sustained. METHODS: Data were collected by Gallup home poll before (spring 2002) and after legislation took effect (spring 2003 and 2004). A representative sample of drivers who owned a cell phone (n = 836 to 966) was interviewed each time. On-road observations were also collected in four cities for 2003 and 2004. RESULTS: Just after the law, 97% of drivers were aware of the new hands free legislation. In sharp contrast to the pre-law rate of 16%, 43% reported not using the phone while driving immediately after the law and 41% one year later. The occasional users especially reduced their use of phones while driving. The law was correlated to reductions in self-reported handheld use of cell phones while driving, from 55.6% pre-law to 15.2% immediately after passage. In spite of this change, however, the hands free legislation did not reduce self-reported involvement of Finnish drivers in phone-related hazards. Handheld usage was still lower in 2004 than pre-law (20.0%), but the 32% increase from 2003 was significant. Observational data collected in Finland in 2003 and 2004 showed an even higher upward trend in handheld use (87% increase, from 3.1% to 5.8%; pre-law data were not available), and matched a similar increase reported by McCartt and Geary (2004) in their observational evaluation of New York's handheld mobile phone law. CONCLUSION: The self-reports indicate that the hands-free law reduced handheld phone use, among occasional users especially, but did not reduce phone-related hazards. The effect of the law on phone use substantially declined within one year.     

驾驶员风险认知能力对交通安全的影响

为辨别不同驾驶员风险认知能力对驾驶安全的影响。通过设置13种存在潜在风险的交通情景,引入惩罚用时机制,利用驾驶模拟器,对熟练驾驶员和非熟练驾驶员在风险认知培训前后的风险认知能力进行比较,找出不同驾驶员对风险认知的差异。试验结果显示,熟练驾驶员的风险认知能力比非熟练驾驶员要高,两者在引起交通风险的因素上是不同的,培训后的风险认知能力较之前有很大提高。培训能够拓宽驾驶员对潜在风险的认知程度,更好地将驾驶员的操作技能、知识体系和外在行为衔接在一起,从而减少交通事故的发生。     

Driving and telephoning: Relative accident risk when using hand-held and hands-free mobile phones

Experimental research shows that using mobile phones while driving leads to impaired driving, and it has been suggested that this driving impairment to a large extent is a result of cognitive, rather than physical, distractions. This notion is partly supported by empirical data showing that use of hands-free phones is associated with impaired driving in much the same way as use of hand-held phones. In the present study, accident risk when using hand-held and hands-free phones was investigated in a sample of 4307 drivers who were involved in accidents in 2007. In addition, data from a similar survey from 1997 (N = 5007) were used in order to get more observations. Relative risk was estimated using “quasi-induced exposure” in multiple-vehicle accidents. Results from the two surveys combined showed a significant increase in accident risk for hand-held mobiles and for hand-held and hands-free phones together. A non-significant tendency towards increased risk for hands-free mobiles was also detected. However, analyses of data from 2007 separately did not result in statistically significant relative risk estimates for any of the mobile types. Hand-held users were more inclined to attribute the accident to mobile phone use than were hands-free users.     

Effects of Washington, D.C. law on drivers' hand-held cell phone use

OBJECTIVE: To assess the effects of Washington, D.C. law prohibiting drivers' use of hand-held cell phones on such use. METHODS: Daytime observations of drivers were conducted at signalized intersections in D.C. in March 2004, several months before the law took effect on July 1, 2004, and again in October 2004. As a comparison, observations also were conducted in areas of Virginia and Maryland located close to the D.C. border. Maryland and Virginia placed no limitations on drivers' phone use. Use was observed for 36,091 vehicles in D.C., 25,151 vehicles in Maryland, and 28,483 vehicles in Virginia. RESULTS: The rate of talking on hand-held cell phones among drivers in D.C. declined significantly from 6.1% before the law to 3.5% after. Phone use declined slightly in Maryland and increased significantly in Virginia so that, relative to the patterns of hand-held phone use in the two states, phone use in D.C. declined 50%. Hand-held phone use in D.C. declined comparably among drivers of vehicles registered in all three jurisdictions. D.C. police issued 2,556 citations and 1,232 warnings for cell phone violations during July-November 2004. There were spates of media coverage when the law was passed and when it took effect. CONCLUSIONS: D.C.'s law prohibiting drivers' hand-held phone use had a strong effect on such use among drivers in D.C. Without ongoing publicized enforcement of the law, long-term compliance may be difficult to achieve.     

Real-world effects of using a phone while driving on lateral and longitudinal control of vehicles

IntroductionTechnologies able to augment human communication, such as smartphones, are increasingly present during all daily activities. Their use while driving, in particular, is of great potential concern, because of the high risk that distraction poses during this activity. Current countermeasures to distraction from phone use are considerably different across countries and not always widely accepted/adopted by the drivers.MethodsThis study utilized naturalistic driving data collected from 108 drivers in the Integrated Vehicle-Based Safety Systems (IVBSS) program in 2009 and 2010 to assess the extent to which using a phone changes lateral or longitudinal control of a vehicle. The IVBSS study included drivers from three age groups: 20–30 (younger), 40–50 (middle-aged), and 60–70 (older).ResultsResults from this study show that younger drivers are more likely to use a phone while driving than older and middle-aged drivers. Furthermore, younger drivers exhibited smaller safety margins while using a phone. Nevertheless, younger drivers did not experience more severe lateral/longitudinal threats than older and middle-aged drivers, probably because of faster reaction times. While manipulating the phone (i.e., dialing, texting), drivers exhibited larger lateral safety margins and experienced less severe lateral threats than while conversing on the phone. Finally, longitudinal threats were more critical soon after phone interaction, suggesting that drivers terminate phone interactions when driving becomes more demanding.ConclusionsThese findings suggest that drivers are aware of the potential negative effect of phone use on their safety. This awareness guides their decision to engage/disengage in phone use and to increase safety margins (self-regulation). This compensatory behavior may be a natural countermeasure to distraction that is hard to measure in controlled studies.Practical ApplicationsIntelligent systems able to amplify this natural compensatory behavior may become a widely accepted/adopted countermeasure to the potential distraction from phone operation while driving.