A 16-second television advertisement for the Hyundai Veloster features the car pulling into the screen, stopping, and sitting motionless in the middle of the road, the driver apparently talking to himself. Two police officers approach, each on a motorcycle, and they stop on either side of the vehicle. After a moment, the two officers pull away without incident and an announcer explains, "There's lots of reasons to love Veloster's voice text messaging. Here's two." The point of the short television ad is to promote the hands-free text messaging system built into the Veloster's dashboard, a novel feature available in many new car models.
The claim implicit in these developmentsand made almost directly in the Hyundai Veloster commercialis: Even though texting with a handheld phone is understood to be so dangerous that it is increasingly outlawed across the globe, hands-free texting while driving is conversely so safe that it should be actively encouraged. In this Viewpoint, I challenge this line of thinking.
The problem with the assumption that hands-free phones should not be distracting to drivers is that a multitude of studies have demonstrated otherwise. A serious problem is now emerging as the automotive industry increasingly builds hands-free calling, texting, and even Facebooking into the dashboards of new cars.
The Science and Policy Context
Multiple countries across the globe have enacted laws against talking and texting on a handheld phone while behind the wheel (see http://www.cellular-news.com/car_bans). In the U.S., 39 states outlaw texting on a handheld phone while driving, and 10 states maintain laws against driving while talking on a handheld phone (http://www.distraction.gov/content/get-the-facts/state-laws.html). But only a very small minority of countries bans hands-free texting or hands-free phone conversation, and no states in the U.S. ban hands-free phone use for all drivers. The implied understanding in such lawsinsofar as only handheld and not hands-free devices are bannedis that it must be the visual and manual interface with the device that causes the driver distraction. However, the preponderance of scientific evidence reveals both handheld and hands-free phone usage to be associated with the same precipitous drop in driving performance.a These findings point to a different understanding of cellphone-related driving impairment than what is implied by the existing traffic laws: it is the conversation that is the source of the distraction. That is, to explain why the large preponderance of evidence shows both handheld and hands-free phones to impair drivers to the same degree, the answer must lie in the mental distraction that comes with talking and listening to someone on the phone.
Just how dangerous is talking on the phone while driving? Research on phone records and accident data indicates a fourfold increase in crash risk for drivers using a handheld or hands-free phone.5 Cellphone-induced driving impairment has even been compared to drunk driving.10 And it is not the case that simply any conversation causes this distraction; evidence is emerging that passenger conversations do not result in the same driving impairment as phone usage. This is because passengers appear to be more aware of driving conditions than are interlocutors on the other end of the phone. Passengers thus modulate conversation when driving conditions change, and even participate in the task of monitoring the road. As Frank A. Drews and his colleagues explain, this difference in driving performance "stems in large part from the changes in the difference in the structure of cellphone and passenger conversation and the degree to which the conversing dyad shares attention."2
The disagreement between the science and the policy over the issue of hands-free phones is exemplified by recent discord between the U.S. government bodies tasked with addressing threats to traffic safety. In December 2011, the National Transportation Safety Board (NTSB) released an official, though in no way binding, recommendation for a ban on all cellphone usage while drivingincluding hands-free devices.6 The response has been mixed. For example, while Secretary of Transportation Ray LaHood has made combating distracted driving a central project of his tenure, he has distanced himself from the NTSB's recommendation, claiming "The problem is not hands-free... That is not the big problem in America." He adds, "Anybody that wants to join the chorus against distracted driving, welcome aboard. If other people want to work on hands-free, so be it."9
On the one hand, I sympathize with the apparent pragmatism of LaHood's strategy. Undeniable legislative progress has been made by aggressively addressing the distraction of handheld phones, especially on the issue of texting while driving. And this progress has come largely without raising the ire of a public and a business community that can be resistant to the regulation of hands-free devices. On the other hand, there are problems with this strategy.
First, when only handheldand not hands-freedevices are subject to regulation, a message is inadvertently sent that hands-free phone usage while driving is safe. But as I noted earlier, the research shows this to be untrue. Second, the gap between the policy and the science is quickly being filled by new hands-free modes of cellular and Internet communication while driving.
The Source of Cellphone-Induced Driving Impairment
Describing the mental distraction of cellphone usage is tricky, especially in the context of a larger discussion in which some participants only acknowledge the visual distraction caused by looking away from the road and the manual distraction of taking a hand off the steering wheel. There are two general ways in which the mental distraction of cellphones has been conceived: inherent cognitive limitations, and long-developed habits of perception.
While researchers agree that cellphone usage results in dangerous driver distraction, there is no explicit consensus explanation of driver distraction in the empirical literature. Still, it is possible to abstract a general theory from the terminology through which these data are often cast: cellphone-induced driver distraction results from a human's inherent cognitive limitations. That is, using a phone and driving a car are understood to be two different tasks, each requiring some of our brain's limited stock of cognitive resources. In this view, the explanation for why cellphone usage results in driving impairment is because the brain does not possess the resources necessary to safely perform these two cognitively demanding tasks at the same time. For example, Tova Rosenbloom summarizes the findings in this way: "the results are in line with the theory of inherent limited capacity of human attention...which predicts that the attentional resources allocated to one task (talking) come at the expense of the other (driving)."8
Cellphone-induced driver distraction results from a human's inherent cognitive limitations.
In my own work, I have suggested an alternative reading of the same data.7 Building on a philosophical tradition called phenomenology, which specializes in the deep description of human experience, I have developed an account of what it is like to use the phone and also what it is like to sit in the driver's seat and operate a vehicle. My contention is that users maintain strong habitual relationships with these technologies. For example, responsible driving requires a driver to have an almost automatic relationship with the car; if a driver must stop the car suddenly, she or he must stomp on the brake pedal at the moment the decision is made. A driver cannot first make the decision to brake, then recall that braking is something that involves pressing a pedal, and then press the brake. Safe driving demands that, through training, the driver has developed responses so automatic that she or he can instead actively focus on the road, on the mirrors, on the movements of other cars, on signs and lights, and such. The habits of the phone lead a user to focus on different things. The phone inclines a user to direct attention to the content of the conversation and to the presence of the person on the other end of the phone. The inclination is to become engrossed in conversation and to have the discussion stand forward within one's overall awareness. My suggestion is that the phone inclines a driver to become absorbed by the phone conversation through a pull much like that of a bad habit. Even if a driver intends to stay focused on the road while talking on the phone, the long-developed habits of the phone may slither in and draw attention toward the conversation.
Whether you prefer the cognitive scientists' explanation that inherent cognitive limitations are to blame for cellphone-related driving impairment, or the alternative suggestion that impairment results from long-developed habitual inclinations to get absorbed by phone conversation, the implications are the same: despite a driver's intentions to drive safely, a dangerous level of distraction is caused by the phone conversation itselfnot by the manual or visual interface with the device.
Hands-Free Dashboard Technologies
The new developments enabling hands-free cellular communication while driving come in two forms. The first are newly emerging voice interface smartphone applications. These are programs that enable usersincluding driversto operate a number of a smartphone's functions through voice command. These include placing a call, dictating text messages, and having incoming text messages read aloud by the computer. The most influential of these is the iPhone's Siri application that offers a discussion-style interface with many of the smartphone's features.
The second form of hands-free communication available to drivers is cellular phone and Internet systems built into a car's dashboard. These new features enable drivers to call and text through voice command. Additionally, the devices may be engaged through buttons and scrolling thumbwheels affixed to the steering wheel or dashboard console, and information may be displayed on screens incorporated into the dashboard. One example is Ford's Sync system, which enables drivers to place hands-free calls, listen to text messages translated into an audio format, and even to reply to texts by sending one of a number of preset responses, such as "Stuck in traffic," and "Can you give me a call?" In an effort to compete with this and other companies offering similar features, General Motors is working to modify its OnStar system to facilitate calls and texting, and also to provide drivers a hands-free method for reading and entering posts on Facebook.3
Despite a driver's intentions to drive safely, a dangerous level of distraction is caused by the phone conversation itself.
In its 2012 guide to new cars, Consumers Digest begins its review of these new dashboard technologies with a brief mention of the NTSB recommendation for the nationwide ban on all in-cab electronicsa ban which, if enacted, would place prohibitions on many of the new technologies the article is about to celebrate. With regard to the ban, the author surmises that, "in any case, we expect that automakers and phone companies will reject the idea as unworkable."4 This seems like an understatement. Carroll Lachnit, an editor at Edmunds.com, makes a sharper observation, "It's a little bit of an arms race... There is a sense among carmakers that if they don't start presenting these kinds of vehicle systems, they will be left in the dust."1
With the development of dashboard-integrated cellular, Internet, and dictation technologies as an exploding area of innovation in the automotive industry, challenges and opportunities are afforded to engineers and computer scientists. But how should these opportunities be pursued? In light of the scientific findings on cellphone-induced driving impairment, practitioners of computer science and engineering ought to develop creative ways to mitigate the dangers of these technologies as they advance. These projects could include, for example, devising more sophisticated options for drivers to preprogram different automated responses tailored to different potential incoming calls, or crafting ways to alert callers that the person on the other end of the phone conversation is behind the wheel.b
Despite the danger science has shown hands-free devices to pose to drivers, the integration of these technologies into dashboards has become a key area of competition for the automotive industry. The Hyundai advertisement mentioned at the beginning of this Viewpoint is just one example of the way hands-free in-cab devices have become the centerpieces of marketing campaigns. And with the failure of the law to move on this issue, responsibility for the safety of pedestrians and the roadways is left exclusively in the hands of drivers.
Using a hands-free cellphone while driving is still legal in most countries, and it is easier than ever as hands-free devices are added to dashboards. This implies it is safe to use a hands-free phone while driving, and encourages you to do it. But it's not, and you shouldn't.
1. Boudreau, J. Coming soon to freeways: Drivers tweeting at 70 miles per hour. Mercury News. (e-edition, updated 2/21/12); www.mercurynews.com/business/ci_19981113?IADID
6. National Transportation Safety Board. No call, no text, no update behind the wheel: NTSB calls for nationwide ban on PEDs while driving. Press Release, Dec. 12, 2011; www.ntsb.gov/news/2011/111213.html.
b. See, for example J. Lindqvist and J. Hong. Undistracted driving: A mobile phone that doesn't distract. In Proceedings of HotMobile 2011:12th Workshop on Mobile Computing Systems and Applications (Phoenix, AZ, Mar. 12, 2011).
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