67 Years Ago

"A grave problem that developed in New Hampshire, spread to Massachusetts, and crept over to Albany, now has all the motor-vehicle commissioners of the eastern states in a wax. It's whether radios should be allowed on cars. Some states don't want to permit them at all - say they distract the driver and disturb the peace. The manufacturers claim that the sound of Rudy Vallee's voice is less disturbing than backseat conversation. Massachusetts leans toward the middle of the road. The commissioner there thinks the things should be shut off while you are driving, but that you should be allowed to take culture with you into the wilderness. The whole problem is getting very complex, but the upshot is that you'll probably be allowed to take your radio anywhere, with possibly some restriction on the times when you can play it."

Written by Nicholas Trott in 1930 -(Courtesy of Lawrence Ashmead, New York City) -as published in The Farmers' Almanac, 1995

1.1 Introduction

Cellular telephones were introduced to the American marketplace in 1983. The early models of these transportable communications devices included large battery packs and carrying cases, and cost thousands of dollars. Only a decade later, cellular telephones are even smaller than a package of cigarettes, and some models are capable of multitasking activities such as transmitting computer files, paging, maintaining continuous communications through e-mail and voice-mail connections, and even "surfing" the Internet.

The Cellular Telecommunications Industry Association (CTIA), the leading national organization which represents both wireless carriers and manufacturers, reports that there are currently over 50 million cellular customers in the United States, with an industry growth rate of about 40% per year. Although this rate is expected to decline in future years, it is estimated that there will be as many as 80 million users by the year 2000.

This rapid growth has brought with it a change in the demographics of cellular telephone users: from middle-aged businessmen to users encompassing all age groups, and social and economic classes, including those with less ability to task-share such as the elderly, and novice and occasional drivers. Facilitating the growth of the user base has been a reduction in the costs for cellular service, which has markedly declined, with an average monthly bill of only $51.00 for local subscribers, many of whom received their telephones for free. The cellular telephone industry is now worth an estimated $19 billion per year and growing. The number of "cell" sites (areas of service) across the nation is rapidly approaching 23,000. Given the moderate costs, availability of service areas, and ease of use, it is not surprising that cellular telephones are being rapidly adopted as fixtures in the American way of life.

In 1995, according to CTIA, approximately 73% of all cellular telephones sold were tiny pocket models (hand-held or "flip-phone"), followed by installed cellular telephones (also called mobile or car phones), and the larger transportable devices (portable cellular telephones). Over 1 in 10 Americans now use cellular telephones, and the usage patterns are continuously changing. In 1990, industry surveys reported that 60% of cellular telephones were used primarily for business purposes, and 40% primarily for personal use. By 1994, this trend began to change, and business use accounted for 44% compared to 56% for personal conversations.

Cellular telephone usage has become so commonplace, that even social norms are being examined. Etiquette columns in newspapers have addressed the proper methods for receiving and placing calls during various social functions. In Chile, where cellular telephones compensate for poor land line service, some restaurants ask their customers to check their phones at the door, and the Long Island Railroad has established a "cellular free" parlor car for those seeking fewer distractions during their commute.

1996, Motorola, Inc. StarTAC

The majority of owners state that they purchased their phones for safety reasons, and many jurisdictions have developed special toll free numbers such as *FHP in Florida, and #77 in Maryland, for the reporting of drunk drivers, motor vehicle collisions and other highway emergencies. Nationally, the CTIA reports that about 18 million cellular calls are made each year to 911 or other emergency numbers. Both the law enforcement and safety communities have been very supportive of such use. In 1995, the J. Stannard Baker Award to a private citizen was bestowed upon Suzanne Peterson who initiated a program in Utah which trained 1,500 cellular subscribers in the best methods to report impaired drivers to law enforcement agencies. And a 1995 survey of consumer support for future automotive technologies conducted by J.D. Power & Associates found that automatic 911 dialing in case of a crash was a very popular feature among prospective car buyers.

1.2 Wireless Communication Technologies

The evolution of wireless technology has seen a number of changes in recent years. While "cellular" communications, based on analog architectures, has dominated the market to date, new technological developments have resulted in the introduction of digital architectures and associated formats as well as competing technologies. Of greatest significance is the ongoing migration from analog to digital formats for cellular carriers. The competing technology, PCS (personal communications services) is based entirely on digital formats and is currently greatly expanding its geographic base to become a formidable competitor to the cellular industry. The improved clarity, security and services potentially available (e.g., high speed data transmission, paging, e-mail, etc.) through the application of digital formats, for both cellular and PCS carriers, will likely see a significant expansion in the customer base in future years. While three digital formats are currently being promoted (Global System for Mobile communications [GSM], Time Division Multiple Access [TDMA], and Code Division Multiple Access [CDMA]), there appears to be little that functionally distinguishes them.

Insofar as available wireless services and capabilities will likely serve as bases for future competition between the two technologies (although some argue there is little difference between the two), there is particular relevance for safety in the use of these technologies while driving, since increasing availability of these services has the potential to increase both use of wireless communications in vehicles, and attentional demands on drivers using these capabilities. Nevertheless, industry projections suggest that it will be 2004 before each wireless architecture (i.e., cellular analog, cellular digital and PCS digital) will have approximately equal numbers of subscribers (Handler, 1997).

1.3 Industry Focus on Safety

Both the cellular equipment manufacturers and the CTIA frequently remind users that driving is their primary responsibility. The cellular industry in general has placed considerable emphasis on safety. In addition, manufacturers of cellular accessories have specifically targeted safety in their products.

For example, in a recent advertisement, Cellular Works stated "Eliminate potential driving hazards with a hands-free Kit from Cellular Works that converts your portable cellular to a car phone. Enjoy crystal clear conversation with both hands safely on the wheel...." Another advertisement follows a similar theme: "Now there's an easier, safer way to use your cellular phone. The CellBaseTM Universal Hands-Free Car Kit lets you keep your hands free... so you can leave them on the wheel. And not only will your driving be safer in terms of other folks on the road, life will be a lot easier inside your car, too. No more flying car phone!"

From the above examples it is apparent that manufacturers clearly recognize the potential risks of in-vehicle cellular telephone use. As a remedy, they encourage the use of hands-free equipment in motor vehicles, along with use of memory-dial capabilities and voice activation features. In addition, the industry emphasizes the safety benefits and the sense of security that can accompany cellular telephone ownership. At the same time, the industry has continued to improve the ease of use features ( at least for installed car phones) for drivers.

In 1995, Prevention Magazine published a 1994 reader survey which found that 41% of adults believe that driving is less risky now than it was in previous years. When asked what habits they had that might cause crashes, 18% reported talking on the phone. In response to industry efforts to further enhance safety, about 80% of car phones being sold for fixed or "permanent" installation in vehicles have the hands-free feature. As stated earlier, however, such installations represent a small share of the market.

Many Americans are using their hand held portable units while driving, and mounting brackets and stands for these phones are widely marketed. One question that arises is whether eliminating the need to hold the phone while using it is enough to ensure safe driving during use. Researchers have only begun to examine the safety implications of phone use while driving. A comprehensive literature review (see Chapter 5 and Appendix C) and analysis of available crash data (see Chapter 3) are presented later in this report.

While the evolution of car (mobile) phones has been toward more "human factored" hands-free systems, the more popular universal portables have become smaller with folding keypad/touchpad architectures ("flip-phones"). Though very popular, the hand held units are typically difficult to operate with one hand, can be easily dropped, and may require more "positioning" by the driver, since they are more likely to experience transmission difficulties due to lower power and an integrated antenna (within the vehicle).

The resulting manual and cognitive "distractions," it has been suggested, may have an even greater adverse influence on driving behavior and performance than "mobile phone" systems (i.e., permanently installed units), under certain conditions. It appears that this is the basis for the focus on hand held cellular telephones by some legislative efforts. A market survey of currently available cellular telephone models and related equipment is included in Appendix B.

1.4 Legislative Initiatives

While the benefits of cellular telephone use frequently have been called out, concern regarding the safety of operating a motor vehicle while using a cellular telephone has been of sufficient magnitude that legislative action has sometimes been initiated. Such action has taken place within the international community and within some U.S. states. In several instances within the international community legislation has, in fact, been adopted, typically allowing the exclusive use of hands-free wireless telephones while driving. In the United States, however, no such attempts have been successful.

As reported in Petica and Bluet (1989), where foreign legislation has been passed, it appears that it has been based on research studies or on empirical observations, although it is not clear what specific findings, observations, or incidents may have prompted the various laws.

International Laws

Petica and Bluet (1989), of the French highway safety research institution (INRETS), conducted a survey among approximately 100 research and policy making institutes in 22 countries. They report that 66% of the responses from industrialized countries (31 responses received) view cellular telephone use by drivers as potentially dangerous, especially when hand held units are used. Only 17% of the respondents believe that there is insufficient data on the subject at this time to support legislation. Another 17% of those surveyed had no opinion.

The survey respondents had a variety of opinions as to which measures would be used to minimize the safety decrements potentially presented by cellular telephone use. The "adoption and application" of regulations was anticipated by 22%, the dissemination of information and educational materials was cited by 39% and standardization of features, and improved ergonomic design was cited by an additional 39%.

The State of Victoria in Australia was apparently the first jurisdiction to address the issue of cellular telephone use in motor vehicles in legislation (in 1988) by banning the use of hand held telephones while driving.1 The State of New South Wales in Australia2 and a number of other nations, have enacted similar bans since that time. These include Spain3, Israel 4, Portugal,5 Italy6, Brazil7, and Chile8. The penalties and fines in Spain (from 10,000 [about $80] to a possible 100,000 pesetas [about $800]) are considered to be the most stringent in Europe to date (Petica and Bluet, 1989).

The legislation of some nations prohibits the use of cellular telephones while driving specifically because it could cause driver distraction. The Swiss Code of Traffic Regulations, for example, prescribes that, "The driver must concentrate on the road and the traffic while driving. He or she may not carry out activities while driving which negatively impact the operation of the vehicle." The Code states specifically that drivers must make sure they are not distracted by radio or other audio devices.9 Switzerland imposes a fine of 100 swiss francs (about $80) for the use of a car phone in a moving vehicle without using a hand-free device.10

Similarly, in Great Britain, Highway Code, Rule 43 (1992) provides, "you must exercise proper control of your vehicle at all times. Do not use a hand held telephone or microphone while you are driving ... Do not speak into a hands-free microphone if it will take your mind off the road. You must not stop on the hard shoulder of a motor way to answer or make a call, except in an emergency." This language is apparently unique in recognizing the potential distraction caused by cellular telephone conversations. The cautions against pulling to the side of the road to make a call conflict with recommendations made by manufacturers in the U.S. to place calls from the road shoulder.

By contrast, France and Sweden have, thus far, chosen to operate under general provisions in their existing driving codes (Petica and Bluet, 1989). French law provides, "the driver of a vehicle must constantly be in position to execute freely and without delay all driving maneuvers."11 The law in Sweden states, "Motor vehicle drivers must take the necessary caution, care and prudence while on the road to avoid traffic accidents." 12

In Germany, the police and Federal Highway Research Institute have collected data which they plan to analyze in 1997. The analysis will be used to determine whether legislation is needed. Meanwhile, Germany's Federal Ministry of Transport advises drivers to use "Freisprechanlage," or hands-free models, while driving.13

Austria and the Netherlands are reportedly considering laws that would restrict cellular telephone use to hands-free units, when the car is parked or when traveling at low speeds (Petica and Bluet, 1989). Japan and Finland have, at least initially, concluded that laws limiting cellular telephone use while driving may not be effective because it is difficult to control behavior (Petica and Bluet, 1989). Copies of many of these laws have been included in this report in Appendix A.

State Laws in the United States

It is unlawful to drive recklessly in every State in the United States. In addition, a number of states have laws on their books that prohibit careless or inattentive driving.

In Delaware, for example, drivers are specifically required by statute "to give full time and attention to the operation of the vehicle." The statute provides that persons who fail to maintain a proper lookout while operating a vehicle "shall be guilty of inattentive driving." New Mexico's law provides that drivers must give their "full time and entire attention to the operation of the vehicle." The law further provides that "any person who operates a vehicle in a careless, inattentive or imprudent manner ... is guilty of a misdemeanor." Careless or inattentive driving is also an offense in Idaho and Wisconsin. Penalties for a first or subsequent violation of inattentive driving in these States include fines ranging from $20 to $400 and, in some cases, imprisonment. In Idaho, a offender could face imprisonment of up to six months in jail.

In one Ohio case14 a conviction was upheld by the Court of Appeals where a driver was cited for operating a motor vehicle without giving full time and attention to its operation. The driver was using a cellular telephone and, while hanging it up, mistakenly began to exit the roadway. When he realized his error, he weaved to re-enter the interstate. While no interference or contact was made with another vehicle, an observing officer cited him for "weaving across curb and center lines of traffic."

To date, however, no State has enacted legislation to specifically limit the use of cellular telephones on the highway. Such legislation has been introduced or considered in a number of States, but none has yet been enacted.

In 1989, for example, a bill was introduced to the Minnesota State Legislature to ban the use of hand-held phones on the highway. Similar bills have been introduced in Arizona, Massachusetts, Virginia and New Jersey (Frisbie, 1991). In 1995 and 1996, proposed bills attempting to address this issue in several States were introduced. None of these bills were enacted. Some of these bills are described below.

Hawaii's bill, H.R. 284, introduced in 1995, was based on a finding that "the increasing use by motorists of cellular radio telephones, or 'car phones,' together with laptop computers, portable facsimile machines, and similar devices, are a potential danger to safe driving in this State, and may constitute a contributing factor in an increasing number of the State's traffic accidents."

The bill noted that "the improper use of such hand-held equipment may be a distraction." If it had been enacted, the bill would have made it unlawful "to operate a cellular radio telephone, computer, facsimile, or other portable or laptop device, which requires holding the unit, or a portion of the unit, with one or both hands in order to operate the unit, while operating a motor vehicle." The legislation would have permitted use of "hands-free" cellular telephones, and would have otherwise permitted cellular telephone use for use in emergency situations, or if the driver had safely pulled over out of the stream of traffic to the shoulder of the road, or to another safe area off the road, and come to a complete stop. A violation of this law would have resulted in a fine of $100, but would not have resulted in the assessment of points. (Similar provisions were proposed also in Hawaii H.R. 341.)

In Virginia, House Bill 1666 would have prohibited the use of a "mobile telephone while operating a motor vehicle ... on the highways of [Virginia] unless at least one of [the driver's] hands remained on the steering wheel ... at all times."

Three acts were introduced in the New York State Legislature for consideration which related to cellular telephone use in motor vehicles. Each act addressed a different aspect of the issue.

• Act 9769 would have made it unlawful for a person to operate a motor vehicle while "using a cellular or car phone." A person convicted of violating this provision would have been subject to a fine of $50.
• Act 9768 would have required that manufacturers of cellular or car telephones affix warning labels to the packages of these products. The act provided that the labels read as follows, "The use of a cellular telephone or car phone while operating a motor vehicle has been known to be the cause of traffic accidents and caution is advised in such use."
• Act 9770 would have required the New York Department of Motor Vehicles to record information relating to the use of cellular or car phones as a contributing factor in crashes, and to report this information annually, starting in 1997. This is the first piece of legislation, of which NHTSA is aware, that attempted to provide specifically for the focused collection of data on cellular telephone involvement in crashes.

It should be noted that Senate Bill 6237 was introduced in 1996 in the Washington State Legislature specifically to permit the use of hands-free telephones. At the time the bill was introduced, Washington State Law prohibited an individual from "wearing a headset or earphones connected to any electronic device capable of receiving radio broadcast or playing a sound recording" while driving. The bill contained an amendment to state specifically that the law was not intended to prohibit motorists from using "hands-free wireless communications systems." The amendment was enacted into law.

A similar provision was considered in Pennsylvania. Pennsylvania Law disallows the use of headphones, earphones or other similar devices while operating a vehicle. In 1995, House Bill 1424 was introduced to permit use of "a headset in conjunction with a cellular telephone that only provides sound through one ear and allows surrounding sounds to be heard with the other ear." This bill did not pass.

The agency is aware of bills under consideration in the Legislatures of six States during 1997, addressing cellular telephone use while driving.

House Bill 0562 was introduced in the State of Illinois in February 1997. If enacted, it would prohibit a driver from using "a telephone while operating the motor vehicle unless the telephone is equipped with and the driver uses an apparatus that allows the driver to talk and listen without holding the telephone or its handset or receiver." The legislation would not permit a driver to hold or touch a telephone, its handset or a receiver while operating a motor vehicle, except "to enable the apparatus, enter a telephone number, ... hang up or turn off the telephone."

Senate Bill 1131, introduced in February 1997 in the State of California, if enacted, would prohibit a person from driving a vehicle "while operating a cellular telephone if the operation of the telephone by the driver requires the driver to hold the telephone in his or her hand."

Oregon's Senate Bill 514, which was introduced in February 1997, would make it an offense, punishable by a fine of up to $75, for a person to drive "while using a mobile telephone if the person uses a mobile telephone while driving or moving a vehicle on a highway." Under this bill, a "mobile telephone" would mean a "hand-held device."

Legislative Bill 338, which was introduced in January 1997 in Nebraska, appears to reach even further. If enacted, this bill would prohibit any person from operating a motor vehicle "while using a cellular telephone," except in limited situations, such as for a medical emergency or if persons reasonably believe they or others are in physical danger. It appears that the bill would prohibit use of both hand-held and hands-free telephones. Persons who cause a collision because they were operating a motor vehicle while using a cellular telephone would be considered to have committed the offense of reckless driving and would be punished accordingly.

In the 220th Legislative Session of the New York State Legislature, four bills were introduced. Two of the bills, if enacted, would prohibit use of a hand held cellular telephone while operating a motor vehicle. Assembly Bill 4444 would make it unlawful for a person to operate a motor vehicle equipped with a "hand held cellular telephone which is in use while operating the vehicle." A person convicted of violating this provision would be subject to a fine of $50. Assembly Bill 5857 would prohibit a driver from operating a motor vehicle "while using a hand held cellular or cellular car telephone." It would provide a grace period of sixty seconds for the receipt and transmission of calls to pull the vehicle off the road and park in a safe location that will not interfere with the flow of traffic, and it would provide an exception for emergency situations. A violation of this provision would constitute an infraction under New York State law and would be punishable by a fine of up to $50. Second and subsequent offenses would be punishable by fines of at least $100 and $200, respectively.

The other two New York bills address the need for additional consideration of and information regarding the issue of cellular telephone use by motorists. Like the proposed legislation that was introduced in the New York State Legislature in 1996, New York's Assembly Bill 4588 (introduced in February 1997) requires the New York Department of Motor Vehicles to record information relating to the use of cellular or car telephones as a contributing factor in crashes, and to report this information annually. In accordance with this bill, reporting would begin in 1998. New York's Senate Bill 3481 would go a step further, by creating a "New York State Task Force on Communications Technology and Driver and Highway Safety." Under the bill, the task force would be charged with studying and recommending a course of action to address the use of cellular telephones while operating a motor vehicle. The recommendations would "be aimed at decreasing the risk of driving accidents due to cellular telephone use while driving" and the study would include:

... issues of highway and traffic safety as they relate to the use of cellular telephones and other communication devices while operating a motor vehicle ... [,] the impact of such recommendations upon businesses and individuals dependent on cellular telephones to conduct business and/or for other important purposes ... [,] innovative technologies being used and/or proposed to be used in motor vehicles cellular telephone usage that may help alleviate risks to highway and traffic safety ... [,] recommendations for public and private strategies to address these issues, as well as public information campaigns to educate and inform our resident and non-resident motorists of dangers associated with cellular telephone use while operating a motor vehicle and methods of lessening such potential dangers.

A bill has been introduced also in the New Jersey Legislature, to study the use of cellular telephones in motor vehicles. Under the bill, Senate Bill 1070, the New Jersey Commissioner of Insurance, the Highway Traffic Safety Policy Advisory Council and the Division of Highway Safety of the Department of Law and Public Safety would be required to collect and evaluate statistics showing whether the use of "manually held and manually dialed cellular telephones or certain other cellular telephones" by motor vehicle operators "has increased the incidence of accidents or accidents per mile of similar motor vehicles." These State officials would also be required to "evaluate and advise whether the use, non-use, or extent of use of cellular telephones by motorists should be proposed as a factor in determining: (a) lower premium rates of motor vehicle insurance policies where appropriate; (b) tort liability in motor vehicle accident law suits; (c) safety instructions given to customers by sellers, installers and lessors of cellular telephones; and (d) any other safety proposal on the use of cellular telephones.

Copies of the proposed bills cited above have been included in this report in Appendix A.

1.5 Objective and Scope

Given the rising number of users of cellular telephones and the increasing number of services available through their use, it has been suggested that there may be a corresponding increase in cellular telephone related crashes. In addition, there have been a growing number of inquiries directed to NHTSA from the public, the media and members of Congress relating to the safety of using cellular telephones while driving. In response to this national level of concern, NHTSA initiated a program of research to develop a comprehensive body of knowledge on the subject. This report reflects one product of that research program.

The objective of this report is to assess the current state of knowledge regarding the impact of cellular telephone use on motor vehicle drivers while driving, and explore the broader safety issues associated with such use.

The primary scope of this report focuses on the potential impact of voice communications on driving. However, continuing development and availability of cellular technologies with integrated office functionality (e.g., network/Internet access, e-mail, paging, etc.) have also raised questions among some observers about the potential implications of such use on traffic safety. Thus, where relevant, consideration is also given to the possible impact of these technological developments.

1.6 Approach

The approach taken in preparing this report included a review of available literature, targeted data collection, focus groups, public opinion and identification of potential links between driver phone use and specific traffic hazards. The information contained in this report is drawn from the broadest range of sources available.

This document reflects the current state of knowledge from a variety of perspectives including the general public, law enforcement personnel, legislators, cellular industry representatives, insurance companies, academia and the government. This comprehensive approach has developed a useful body of information while also defining areas in which additional targeted research would be beneficial. It is hoped that this information will be useful to the states in addressing the issue of cellular telephone use and safety, to the industry in optimizing the design and implementation of cellular technologies for safety, and to the driving public in using these communications and associated technologies appropriately.

1.7 Organization of this Report

This "Investigation of the Safety Implications of Wireless Communications in Vehicles" is designed to present all available information, from human factors and crash investigation researchers, legislatures, law enforcement, public surveys, industry representatives, and the commercial marketplace, in a format that will allow the reader to examine and evaluate many aspects of the issues associated with cellular telephone use and driving.

The report begins with an overview of "Cellular Telephone Use in America." It presents results from public surveys which describe the changing demographics of the user population. The common business and personal usage patterns of subscribers, and the impact of such use on emergency identification and response is presented. This section also provides a closer look at phone user opinions on the safety of cellular telephone use while driving.

Chapter 3 discusses available crash information. There is a dearth of statistics with regard to cellular telephone related pre-crash factors. All available information from the federally sponsored Fatal Analysis Reporting System (FARS), and the National Automotive Sampling System (NASS) are shown.

Oklahoma and Minnesota are the only two states that attempt to systematically record cellular telephone use prior to a crash. Their data and the limitations of the data collection methodologies are reviewed. The Japanese National Police Agency conducted a focused crash investigation program during June, 1996. The results of that project do not necessarily apply to American driving situations, but do allow for interesting comparisons and contrasts with U.S. data. Individual case studies are also included which demonstrate the circumstances that can lead to a serious crash.

The "Analysis of Police Crash Report Narratives" involving cellular telephone usage in Chapter 4 represents a study drawn from an analysis of the narrative sections of selected (i.e., cellular telephone related) Police Crash Reports from North Carolina. The multi-year analysis shows that the number of cellular telephone related crashes is increasing in concert with the growing number of users. The study also identifies individuals using computers and other devices as crash antecedents.

Chapter 5 is a comprehensive review of simulator, and on-the-road, instrumented vehicle research conducted on cellular telephone use while driving. Available epidemiological studies are also reviewed. A critical analysis of these studies demonstrates their applicability to real world driving situations, and addresses their limitations, given the complexities of cellular telephone use in the driving environment.

The final chapter (Chapter 6), provides a discussion of what was learned in conducting this research and assembling this report. It identifies common threads drawn from the myriad of sources. The implications of the rapid introduction of cellular communications devices into the driving environment have not been adequately addressed by existing data collection systems. Thus, the discussion also focuses on what is still not known or well understood. The initiation of targeted research in a number of arenas is recommended.

The appendices provide copies of selected legislation, acknowledgments of contributions, a glossary of cellular technology terms, a list of references, a survey of cellular communications devices currently available and in use in motor vehicles, comprehensive critical reviews of the cellular telephone research studies presented in Chapter 5 and a discussion of human factors considerations for the design of cellular telephones that can influence the safety of their use from a moving vehicle.

1.8 Definition of Terms

In discussing the potential for cellular telephone use to adversely influence driving behavior and performance, the terms "cognitive," "cognitive capture" and "emotional content" are used. Within the context of this report, these terms describe the nature and degree of attention distributed between the tasks of driving and conversing on the phone. The task of conversing is seen as potentially having a major cognitive (thought) component where attention is focused on conversation rather than driving. The extent to which this occurs can significantly influence situational awareness (e.g., of the actions of other vehicles, the presence of a stop sign, etc.).

Cognitive capture refers to the situation where the driver may be totally "lost in thought," a condition which, in particular, could impair situational awareness. Where emotional content (i.e., personal involvement) in a conversation is high, such as arguing with someone over the phone, the likelihood of cognitive capture is increased. Those instances that require some level of cognitive involvement leading to a loss of situational awareness are viewed as increasing the risk of a crash.

Throughout this report, the phrase "cellular telephone" is used to designate the wireless communications hardware of interest. However, as pointed out earlier, a new, competing technology has emerged that also incorporates a similar architecture (i.e., handset) and hence similar concerns for safe use while driving. These Personal Communications Services (PCS) devices share many, if not all the display, control, implementation and user issues that have been associated with cellular telephone use in vehicles.

Since all of the research and data reviewed in this report has focused on "cellular telephones," this phraseology has been adopted throughout this report to simplify the presentation of materials. However, the discussion of issues and recommendations provided in this report apply to all wireless communications systems and associated hardware that might be used by drivers of vehicles.