Mobile phone use while driving is common, but it is widely considered dangerous due to its potential for causing distracted driving and accidents. Due to the number of accidents that are related to cell phone use while driving, some jurisdictions have made the use of a cell phone while driving illegal. Many jurisdictions have enacted laws to ban handheld mobile phone use. Nevertheless, many jurisdictions allow use of a hands-free device, in which the driver talks using a microphone and a speakerphone. Driving while using a handsfree cellular device is not safer than using a hand held cell phone, as concluded by case-crossover studies, epidemiological, simulation, and meta-analysis. In some cases restrictions are directed only at minors, those who are newly qualified license holders (of any age), or to drivers in school zones. When mobile phones were first introduced, they were typically only able to make voice calls. In the 2000s, as cell phone technology developed, and smartphone usage increased, cell phones can also be used to read or type text messages, surf the Internet and view videos. Activities such as texting while driving can also increase the risk of an accident.
The Société de l'assurance automobile du Québec (SAAQ), the provincial automobile insurance association in Quebec, conducted a study in on driving and cellphones in 2003. Questionnaires were sent to 175,000 drivers and analysis was done on the 36,078 who responded. The questionnaire asked about driving habits, risk exposure, collisions over the past 24 months, socio-demographic information, and cell phone use. Questionnaires were supported with data from cell phone companies and accident records held by police. The study found that the overall relative risk (RR) of having an accident for cell phone users when compared to non-cell phone users averaged 1.38 across all groups. When adjusted for kilometers driven per year and other crash risk exposures, RR was 1.11 for men and 1.21 for women. They also found that increased cell phone use correlated with an increase in RR. When the same data were reanalyzed using a Bayesian approach, the calculated RR of 0.78 for those making less than 1 call/day and 2.27 for those with more than 7 calls/day was similar to cohort analysis. When the data were reanalyzed using case-crossover analysis, RR was calculated at a much higher 5.13. The authors expressed concern that misclassification of phone calls due to reporting errors of the exact time of the collisions was a major source of bias with all case-crossover analysis of this issue.
In March 2011 a US insurance company, State Farm Insurance, announced the results of a study which showed 19% of drivers surveyed accessed the Internet on a smart phone while driving. In September 2010, the US National Highway Traffic Safety Administration (NHTSA) released a report on distracted driving fatalities for 2009. The NHTSA considers distracted driving to include some of the following as distractions: other occupants in the car, eating, drinking, smoking, adjusting radio, adjusting environmental control, reaching for object in car, and cell phone use. In 2009 in the US, there was a reported 5,474 people killed by distracted drivers. Of those 995 were considered to be killed by drivers distracted by cell phones. The report doesn't state whether this under or over represents the level of cell phone use amongst drivers, and whether there is a causal relationship.
A 2003 study of US crash data states that driver inattention is estimated to be a factor in 20% to 50% of all police-reported crashes. Driver distraction, a sub-category of inattention, has been estimated to be a contributing factor in 8% to 13% of all crashes. Of distraction-related accidents, cell phone use may range from 1.5 to 5% of contributing factors. However, large percentages of unknowns in each of those categories may cause inaccuracies in these estimations. A 2001 study sponsored by the American Automobile Association recorded "Unknown Driver Attention Status" for 41.5% of crashes, and "Unknown Distraction" in 8.6% of all distraction related accidents. According to NHTSA, "There is clearly inadequate reporting of crashes".
Currently, being distracted by an "outside person, object, event" (commonly known as "rubbernecking") is the most reported cause of distraction-related accidents, followed by "adjusting radio/cassette/CD". "Using/dialing cell phone" is eighth. A 2003 study by the University of Utah psychology department measured response time, following distance, and driving speed of a control group, subjects at the legal blood alcohol content (BAC) limit of 0.08%, and subjects involved in cell phone conversations. As the study notes; "... this is the third in a series of studies that we have conducted evaluating the effects of cell phone use on driving using the car following procedure (see also Strayer & Drews, 2004; and Strayer et al., 2003). Across these three studies, 120 participants performed in both baseline and cell phone conditions. Two of the participants in our studies were involved in an accident in baseline conditions, whereas 10 participants were involved in an accident when they were conversing on a cell phone." However zero (0) drunk drivers had accidents in any of the tests. After controlling for driving difficulty and time on task, the study concluded that cell phone drivers exhibited greater impairment than intoxicated drivers.
A 2005 review by the Hawaiian legislature entitled "Cell Phone Use and Motor Vehicle Collisions: A Review of the Studies" contains an analysis of studies on cell phone/motor vehicle accident causality. A key finding was that: "No studies were found that directly address and resolve the issue of whether a causal relation exists between cellular telephone use while operating a motor vehicle and motor vehicle collisions." Meta-analysis by the Canadian Automobile Association and the University of Illinois found that response time while using both hands-free and hand-held phones was approximately 0.5 standard deviations higher than normal driving (i.e. an average driver, while talking on a cell phone, has response times of a driver in roughly the 40th percentile).
In the US, the number of cell phone subscribers has increased by 1,262.4% between the years 1985-2008. In approximately the same period the number of crashes has fallen by 0.9% (1995–2009) and the number of fatal crashes fallen by 6.2%. It has been argued that these statistics contradict the claims that mobile use impairs driving performance. Similarly, a 2010 study from the Highway Loss Data Institute published in February 2010 reviewed auto claims from three key states along with Washington D.C. prior to cell phone bans while driving and then after. The study found no reduction in crashes, despite a 41% to 76% reduction in the use of cell phones while driving after the ban was enacted.
Driving while using a handsfree cellular device is not safer than using a hand held cell phone, as concluded by case-crossover studies, epidemiological, simulation, and meta-analysis. The increased cognitive workload involved in holding a conversation, not the use of hands, causes the increased risk. For example, a Carnegie Mellon University study found that merely listening to somebody speak on a phone caused a 37% drop in activity in the parietal lobe, where spatial tasks are managed. The consistency of increased crash risk between hands-free and hand held cell phone use is at odds with legislation in many locations that prohibits hand held cell phone use but allows hands-free.
The scientific literature is mixed on the dangers of talking on a cell phone versus those of talking with a passenger. The common conception is that passengers are able to better regulate conversation based on the perceived level of danger, therefore the risk is negligible. A study by a University of South Carolina psychology researcher featured in the journal, Experimental Psychology, found that planning to speak and speaking put far more demands on the brain’s resources than listening. Measurement of attention levels showed that subjects were four times more distracted while preparing to speak or speaking than when they were listening. The Accident Research Unit at the University of Nottingham found that the number of utterances was usually higher for mobile calls when compared to blindfolded and non-blindfolded passengers across various driving conditions. The number of questions asked averaged slightly higher for mobile phone conversations, although results were not constant across road types and largely influenced by a large number of questions on the urban roads.
A 2004 University of Utah simulation study that compared passenger and cell-phone conversations concluded that the driver performs better when conversing with a passenger because the traffic and driving task become part of the conversation. Drivers holding conversations on cell phones were four times more likely to miss the highway exit than those with passengers, and drivers conversing with passengers showed no statistically significant difference from lone drivers in the simulator. A study led by Andrew Parkes at the Transport Research Laboratory, also with a driving simulator, concluded that hands-free phone conversations impair driving performance more than other common in-vehicle distractions such as passenger conversations. However, some have criticized the use of simulation studies to measure the risk of cell-phone use while driving since the studies may be impacted by the Hawthorne effect. This is type of reactivity in which individuals modify or improve an aspect of their behavior in response to their awareness of being observed.
In contrast, the University of Illinois meta-analysis concluded that passenger conversations were just as costly to driving performance as cell phone ones. AAA ranks passengers as the third most reported cause of distraction-related accidents at 11%, compared to 1.5% for cellular telephones. A simulation study funded by the American Transportation Research Board concluded that driving events that require urgent responses may be influenced by in-vehicle conversations, and that there is little practical evidence that passengers adjusted their conversations to changes in the traffic. It concluded that drivers' training should address the hazards of both mobile phone and passenger conversations.
The scientific literature on the dangers of driving while sending a text message from a mobile phone, or texting while driving, is limited. A simulation study at the Monash University Accident Research Centre has provided strong evidence that both retrieving and, in particular, sending text messages has a detrimental effect on a number of critical driving tasks. Specifically, negative effects were seen in detecting and responding correctly to road signs, detecting hazards, time spent with eyes off the road, and (only for sending text messages) lateral position. Surprisingly, mean speed, speed variability, lateral position when receiving text messages, and following distance showed no difference. A separate, yet unreleased simulation study at the University of Utah found a sixfold increase in distraction-related accidents when texting.
The low number of scientific studies may be indicative of a general assumption that if talking on a mobile phone increases risk, then texting also increases risk, and probably more so. Market research by Pinger, a company selling a voice-based alternative to texting reported that 89% of US adults think that text messaging while driving is "distracting, dangerous and should be outlawed." The AAA Foundation for Traffic Safety has released polling data that show that 87% of people consider texting and e-mailing while driving a "very serious" safety threat, almost equivalent to the 90% of those polled who consider drunk driving a threat. Despite the acknowledgement of the dangers of texting behind the wheel, about half of drivers 16 to 24 say they have texted while driving, compared with 22% of drivers 35 to 44.
Texting while driving received greater attention in the late 2000s, corresponding to a rise in the number of text messages being sent. Over a year approximately 2,000 teens die from texting while driving. Texting while driving attracted interest in the media after several highly publicized car crashes were caused by texting drivers, including a May 2009 incident involving a Boston trolley car driver who crashed while texting his girlfriend. Texting was blamed in the 2008 Chatsworth train collision which killed 25 passengers. Investigations revealed that the engineer of that train had sent 45 text messages while operating.
In a 2011 study it was reported that over 90% of college students surveyed text (initiate, reply or read) while driving. On July 27, 2009, the Virginia Tech Transportation Institute released preliminary findings of their study of driver distraction in commercial vehicles. Two studies, comprising about 200 long-haul trucks driving 3 million combined miles, used video cameras to observe the drivers and road; researchers observed "4,452 safety-critical events, which includes crashes, near crashes, crash-relevant conflicts, and unintended lane deviations." 81% of the safety critical events had some type of driver distraction. Text messaging had the greatest relative risk, with drivers being 23 times more likely to experience a safety-critical event when texting. The study also found that drivers typically take their eyes off the forward roadway for an average of four out of six seconds when texting, and an average of 4.6 out of the six seconds surrounding safety-critical events.
In 2013 it was reported that, according to a national survey in the US, the number of drivers who reported using their cellphones to access the internet while driving had risen to nearly one of four.
A study conducted by the University of Illinois using the theory of planned behavior identified two key determinants of high-level mobile phone use. Those two factors, subjective norm (i.e., perceived social norms) and self-identity (i.e., the degree to which individuals see mobile phones as a part of their self), might be promising targets for the development of persuasive strategies and other interventions aimed at reducing inappropriate and problematic use of mobile phones, such as using mobile phones while driving.
Accidents involving a driver being distracted by talking on a mobile phone have begun to be prosecuted as negligence similar to speeding. In the United Kingdom, from 01 March 2017, motorists who are caught using a hand-held mobile phone while driving will have six penalty points added to their license in addition to the fine of £200. This increase was introduced to try to stem the increase in drivers ignoring the law. Japan prohibits all mobile phone use while driving, including use of hands-free devices. New Zealand has banned hand held cellphone use since 1 November 2009. Many states in the United States have banned texting on cell phones while driving. Illinois became the 17th American state to enforce this law. As of July 2010, 30 states had banned texting while driving, with Kentucky becoming the most recent addition on July 15.
Public Health Law Research maintains a list of distracted driving laws in the United States. This database of laws provides a comprehensive view of the provisions of laws that restrict the use of mobile communication devices while driving for all 50 states and the District of Columbia between 1992, when first law was passed, through December 1, 2010. The dataset contains information on 22 dichotomous, continuous or categorical variables including, for example, activities regulated (e.g., texting versus talking, hands-free versus handheld), targeted populations, and exemptions.
In 2014, various state police forces in Australia have trialled cameras which have the ability to pick up errant drivers from more than 500 metres (1,600 ft) away. Police in Western Australia makes use of undercover motorcycles to keep an eye on other motorists and any offence will be recorded on the officer's helmet camera. Other countries with high levels of car crashes relating to distracted driving are also considering similar measures.
NSW road rules were changed on 1 Dec 2016 for P2 drivers. Learner, P1 and P2 drivers must not use mobile phones for any function while driving or riding or while stationary (at traffic lights). You must be parked out of traffic to use your phone. 
The Road Transport Legislation Amendment (Mobile Phones—P2 Licences) Regulation 2016 under the Road Transport Act 2013 enforces this new rule and the the objects of this Regulation sought: (a) to amend the Road Rules 2014 to extend the restriction on drivers who are holders of learner or provisional P1 licences from using a mobile phone while driving a vehicle (whether or not the mobile phone is held by the driver) to include drivers who are holders of provisional P2 licences, and (b) to make consequential amendments to the Road Transport (Driver Licensing) Regulation 2008.
This Regulation was made under the Road Transport Act 2013.
Prior to the introduction of this new law on 1 December 2016, only learner and P1 provisional licence-holders were barred from using mobile phones in any capacity while driving, as P2 drivers faced the same restrictions as other licence-holders.
Countries where using either a hand-held or hands-free phone while driving is illegal:
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Countries where using a hand-held phone while driving is illegal: