4
CURRENT EXPERIENCE WITH SEAT BELT USE TECHNOLOGIES

Ford Motor Company was the first automobile manufacturer to introduce an enhanced belt reminder system in the United States. Selected Model Year (MY) 2000 passenger vehicles were equipped with a light and chime system that embodies more than the 4- to 8-second light and buzzer system required by the National Highway Traffic Safety Administration (NHTSA). In Europe, development of generic specifications for seat belt reminder systems began in 1995, and belt reminder systems are currently available in several vehicles for sale in the European market.

The effectiveness and acceptability of new enhanced belt reminder systems and other in-vehicle technologies to increase belt use currently being introduced on a voluntary basis by the automobile industry are reviewed in this chapter. The information is drawn from briefings to the study committee by key automobile manufacturers, a literature review, and the results of interviews and focus groups conducted by NHTSA specifically for the present study. The chapter ends with a summary of the state of knowledge.

CHARACTERISTICS OF NEW SEAT BELT USE TECHNOLOGIES

Enhanced Belt Reminder Systems

Ford Motor Company introduced the BeltMinder, a registered company trademark, on selected MY 2000 vehicles. By MY 2002, all Ford vehicles were equipped with the enhanced belt reminder for the driver, with a phase-in for the right front-seat passenger starting with MY 2003 vehicles. The BeltMinder complies with the NHTSA regulation for a 4- to 8-second reminder; however, after a pause, the enhanced reminder flashes and chimes intermittently—activating for 6 seconds, then pausing for 30 seconds—for up to 5 minutes if the driver (or passenger) fails to buckle up.

After the introduction of the BeltMinder, NHTSA Administrator Dr. Jeffrey Runge urged other automobile manufacturers to follow Ford’s



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Buckling Up: Technologies to Increase Seat Belt Use 4 CURRENT EXPERIENCE WITH SEAT BELT USE TECHNOLOGIES Ford Motor Company was the first automobile manufacturer to introduce an enhanced belt reminder system in the United States. Selected Model Year (MY) 2000 passenger vehicles were equipped with a light and chime system that embodies more than the 4- to 8-second light and buzzer system required by the National Highway Traffic Safety Administration (NHTSA). In Europe, development of generic specifications for seat belt reminder systems began in 1995, and belt reminder systems are currently available in several vehicles for sale in the European market. The effectiveness and acceptability of new enhanced belt reminder systems and other in-vehicle technologies to increase belt use currently being introduced on a voluntary basis by the automobile industry are reviewed in this chapter. The information is drawn from briefings to the study committee by key automobile manufacturers, a literature review, and the results of interviews and focus groups conducted by NHTSA specifically for the present study. The chapter ends with a summary of the state of knowledge. CHARACTERISTICS OF NEW SEAT BELT USE TECHNOLOGIES Enhanced Belt Reminder Systems Ford Motor Company introduced the BeltMinder™, a registered company trademark, on selected MY 2000 vehicles. By MY 2002, all Ford vehicles were equipped with the enhanced belt reminder for the driver, with a phase-in for the right front-seat passenger starting with MY 2003 vehicles. The BeltMinder complies with the NHTSA regulation for a 4- to 8-second reminder; however, after a pause, the enhanced reminder flashes and chimes intermittently—activating for 6 seconds, then pausing for 30 seconds—for up to 5 minutes if the driver (or passenger) fails to buckle up. After the introduction of the BeltMinder, NHTSA Administrator Dr. Jeffrey Runge urged other automobile manufacturers to follow Ford’s

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Buckling Up: Technologies to Increase Seat Belt Use lead and provide effective belt reminder systems or other appropriate technologies for increasing belt use.1 Most of the major manufacturers responded that they were either studying or near to deploying enhanced belt reminder systems, some as early as 2003.2 Most plan to introduce driver-side systems first, many at the same time as the introduction of advanced air bags. Front-passenger systems will not appear in significant volumes until MYs 2004 and 2005.3 At the time of the present study, the Ford BeltMinder was the only commercially available system in the U.S. market. All first-generation enhanced belt reminder systems deployed or under development for the U.S. market use a sequence of light and chime reminders4 separated by a pause or a light-only interval from the initial 4- to 8-second “federal” light and chime system (see Box 4-1 for examples of systems). The enhanced systems vary in their loudness, urgency, and duration. They all include a speed or distance trigger, reflecting General Motors’ findings that most drivers fasten their seat belts after the engine is started or when the vehicle is in gear or moving slowly. Only about 30 percent of drivers fasten their belts before starting the engine.5 The systems are currently offered for drivers and front-seat occupants, reflecting the availability of front-seat sensors that are or will soon be available on all U.S. vehicles to support the introduction of advanced air bags. The incremental cost of installing the enhanced reminder system is modest.6 In contrast, no manufacturer is offering reminder systems for rear-seat occupants. The absence of rear-seat sensors to detect the presence of rear-seat occupants, the complexities of integrating reliable reminder systems with rear child seats and remov- 1 The first appeal was contained in a letter dated February 25, 2002. A follow-up letter was sent on March 24, 2003. 2 The responses from individual companies can be found in the NHTSA Docket No. 13226 in the U.S. Department of Transportation’s electronic docket system (dms.dot.gov). 3 This information was provided in the manufacturer briefings to the committee and in follow-up inquiries. 4 According to some manufacturers, voice-synthesized systems are considered problematic in a global market. 5 These findings, from research conducted in May 1999, can be found in General Motors’ response to Administrator Runge’s 2002 letter in the NHTSA Docket No. 13226. 6 Several of the manufacturers who briefed the committee at its December 2002 meeting provided more precise cost data for belt reminder systems but indicated that the information is proprietary. Hence the report cannot provide detailed cost data.

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Buckling Up: Technologies to Increase Seat Belt Use Box 4-1 Description of Selected Seat Belt Reminder Systems Ford BeltMinder: After the 4- to 8-second NHTSA-required reminder, the Ford system resumes a warning chime and flashing light at approximately 65 seconds if the driver remains unbuckled while the engine is running and the vehicle is moving at more than 3 mph (4.8 km/h). The system flashes and chimes for 6 seconds, then pauses for 30 seconds, and repeats this cycle of 6-second flashing lights and chimes and 30-second pauses for up to 5 minutes. The system can be disabled for a single trip by buckling the seat belt. It can be permanently disabled by following a series of instructions in the driver’s manual. The BeltMinder is currently available for the driver on all Ford, Lincoln, and Mercury models and has been introduced for front-seat passengers on selected MY 2003 Ford, Lincoln, and Mercury models. DaimlerChrysler belt reminder system: After the 4- to 8-second NHTSA-required reminder, the DaimlerChrysler system resumes a steady warning light if the driver is still not buckled. After 30 seconds, if the driver remains unbuckled and the vehicle is moving at more than 15 mph (24 km/h), a multistage progressive chime and flashing light commence and are emitted for a maximum of 60 seconds. The warning light remains permanently illuminated if the driver is still unbuckled after this time. A driver and front-seat passenger system will be phased in over the next several years on all Mercedes-Benz vehicles for sale in the United States. The system, which can be disabled in a Mercedes-Benz retail center, will be available on some MY 2005 vehicles and on all MY 2006 Mercedes-Benz vehicles. Chrysler, Dodge, and Jeep vehicles will have at least a driver-side system by MY 2006.

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Buckling Up: Technologies to Increase Seat Belt Use General Motors belt reminder system: Immediately after the 4- to 8-second NHTSA-required reminder, the General Motors (GM) system resumes a steady light for 12 more seconds if the driver does not buckle up. If the driver remains unbelted, a flashing light and limited chime commence for 55 seconds, followed by 30 seconds of silence. The system repeats the full cycle if the driver remains unbelted and the vehicle is traveling at 5 mph (8 km/h) or more. The cycle is followed by a 3-minute period of silence and repeats for a third and final time if the driver continues to ride unbelted. All warning functions stop when the belts are buckled. The system cannot be disabled. GM belt reminder systems are projected to be introduced on selected MY 2005 vehicles, some with driver-side only systems, and others with driver- and passenger-side systems. Toyota belt reminder system: After the 4- to 8-second NHTSA-required reminder, the Toyota system resumes with a flashing light and mild buzzer for 10 seconds if the driver remains unbuckled and the vehicle is moving at more than 9 mph (14.5 km/h). If the driver remains unbuckled, the flashing light continues and the buzzer will sound in a more intense tone for 20 more seconds. If the vehicle speed drops below 9 mph within that time, the buzzer sound will continue. If the driver has not buckled up after the 20-second period, the flashing light continues but the buzzer ceases. The system can be deactivated by a series of steps. A driver-only light and buzzer system will be introduced on the MY 2004 Prius, and several 2005 models will have a light and buzzer system for the driver and front-seat passenger.

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Buckling Up: Technologies to Increase Seat Belt Use able backseats, and lower rear-seat occupancy rates currently make rear-seat systems appear relatively costly. For now, the manufacturers are offering systems that indicate to the driver whether rear-seat passengers have failed to put on or have unbuckled their belts during a trip.7 All the systems, with the exception of General Motors’ belt reminder, provide mechanisms to disconnect the system, either for a single trip or permanently.8 In Europe, the introduction of enhanced belt reminder systems began with a Swedish National Road Authority (SNRA) initiative in 1995. A special working group of researchers, insurance companies, and the automobile industry was formed to develop generic specifications for a seat belt reminder system (Fildes et al. 2002, 3). The specifications took into account some of the shortcomings of the early U.S. interlock systems, which were unable to differentiate between driving and low-speed maneuvers, such as parking or going in reverse. Thus, the new systems activate only after a specified minimum speed has been reached, or after a specified time or distance. The European specifications have been incorporated in the European New Car Assessment Program (EuroNCAP), a consumer safety information program modeled on NHTSA’s NCAP.9 As an incentive to industry, EuroNCAP offers manufacturers up to 3 points out of a total of 37—the difference between a four-star and the top five-star rating of European automobiles—for seat belt reminder systems that meet certain minimum performance criteria (see Box 4-2). In 1999, Saab was the first company to develop a prototype seat belt reminder system that was consistent with the SNRA and subsequently the EuroNCAP reminder system specifications. Today, several vehicles for sale in the European market have belt reminder systems that meet EuroNCAP specifications. 7 International Electronics and Engineering S.A. (IEE), a European sensor manufacturer, is currently working with three European car manufacturers on specifications for a rear-seat belt reminder system. IEE is leading a feasibility study on the development of rear-seat sensors and on the solution of problems related to removable seats, child restraints, and other technical obstacles (personal communication with Paul Schockmel, IEE, June 12, 2003). 8 A permanent disconnection typically requires a series of steps that are detailed in the owner’s manual. 9 EuroNCAP Belt Reminder Assessment Protocol, Doc 61b, Version November 2002, contains the most recent specifications.

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Buckling Up: Technologies to Increase Seat Belt Use Box 4-2 EuroNCAP Protocols for Belt Reminder Systems Manufacturers may receive points for belt reminder systems on the basis of system coverage and compliance with certain performance criteria. The most recent specifications of which the committee was aware are contained in the EuroNCAP Belt Reminder Assessment Protocol, Doc 61b, Version November 2002. System coverage: One point is given for systems that cover the driver, one point for systems that also cover the front-seat passenger, and a final point for systems that extend to rear-seat passengers, for a total of three possible points. Because of the complexities and perceived costs of installation of rear-seat reminder systems, a system that notifies the driver of the belt use status of rear-seat occupants may be substituted for audio and visual signals for the time being. System activation: Systems should alert front-seat occupants with sound and light only if the seat belts are not in use. Minimum thresholds of use are defined. For example, the audiovisual reminder should be activated if the car is used for more than 60 seconds, is being driven at speeds greater than 25 km/h (16 mph), or is driven a distance of more than 500 meters (547 yards). If the system includes an immediate alert more sophisticated than a simple sound signal (like a text or voice message), the start of the audiovisual reminder can be postponed for another 30 seconds or 500 meters, and the speed criterion can be increased to 40 km/h (25 mph). Auditory signal loudness: The auditory signal should be at least 65 dB, should be loud and clear under normal driving conditions, and should become increasingly aggressive the longer the seat belt remains unfastened. “Normal” conditions are defined as 50 km/h (31 mph) in top gear on a good asphalt road with the ventilation fan running at 75 percent (Fildes et al. 2002, 8).

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Buckling Up: Technologies to Increase Seat Belt Use System duration: The reminder system should be active for at least 90 seconds, with quiet periods of no longer than 25 seconds. Disconnection: The system may provide a means of disconnection for a single trip, but it should be more complicated than simply buckling the belt. Permanent disconnection may be available to the owner on demand, but the information should not be provided in the owner’s manual. Interlock Systems The 1970s experience with interlock systems still influences technology decisions by the automobile manufacturers for the sale of vehicles in the U.S. market. For example, no company is developing an interlock system for sale in the U.S. market as original equipment on vehicles intended for the general public because of concern about potential negative customer reaction. Interlock systems, however, are being developed for special fleets and aftermarket applications. For example, D&D Innovations, Inc., a small manufacturer, is currently marketing an aftermarket device that can be installed in vehicles already equipped with gearshift locks (locks that prohibit a vehicle from being put into gear if the vehicle’s brake is not depressed). The interlock system prevents the vehicle from being put into gear if the driver and passenger are not buckled up at the start of the trip. (Chime and light sequences sound if driver or passenger unbuckles during a trip.) D&D Innovations is targeting the seat belt shifter lock to owners of fleet vehicles as well as to parents of teenage drivers—a high-crash-risk group. In the United States, 16-year-olds have almost 10 times the crash risk of drivers aged 30 to 59, and almost 3 times the risk of older teenage drivers (IIHS and Traffic Injury Research Foundation 2003, 1). D&D Innovations is also working with General Motors so that the shifter lock can be made available as a dealer-installed option. According to D&D Innovations, the cost of the device is less than $200 for aftermarket applications. The cost could be as low as $65 if production volumes were large enough.

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Buckling Up: Technologies to Increase Seat Belt Use Another option for seat belt interlocks involves an interlock system that works with a vehicle’s entertainment systems rather than its gearshifts. For example, if a driver does not respond to a light and chime seat belt reminder that commences when the vehicle is started, the radio or CD player could be made inoperative until the driver or front-seat passenger buckles up. Although an entrepreneur has petitioned NHTSA’s Chief Counsel regarding the legality of an entertainment interlock system he had developed, such a system is not currently being manufactured for sale, either as original equipment or for aftermarket applications. Development of interlock systems for specific aftermarket applications is not without precedent. For example, the experience with alcohol ignition interlocks has been encouraging. The devices can be effective in reducing impaired driving by convicted offenders. However, in the United States, the practical effectiveness of alcohol interlocks has been limited by their cost and by the small number of offenders willing to install them to drive legally (Voas et al. 2002, 449; DeYoung 2002, 473). North Carolina, Pennsylvania, and California, among other states, have begun to mandate the installation of alcohol interlocks as a prerequisite for DUI offenders to apply for restricted licenses. The effectiveness of seat belt interlocks for high-risk drivers will also likely depend on the extent to which the states and the courts are willing to require their use. EVIDENCE OF EFFECTIVENESS AND ACCEPTABILITY OF NEW SEAT BELT USE TECHNOLOGIES Manufacturers’ Briefings At the second committee meeting in Dearborn, Michigan, four automobile manufacturers—General Motors, DaimlerChrysler, Ford, and Toyota—briefed the committee on the development status of seat belt use technologies and on company studies and market research on the effectiveness and acceptability of the new technologies. The committee also heard from D&D Innovations, Inc. Because the briefings were held in closed sessions to safeguard proprietary information, not all details can be disclosed.

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Buckling Up: Technologies to Increase Seat Belt Use The automobile manufacturers indicated that consumer acceptability is key to the success of new technology introduction, and hence they favor systems that provide a balance between effectiveness and acceptability. Their primary focus is on enhanced belt reminder systems that target part-time users—those who forget to buckle up or who find it uncomfortable or inconvenient on short trips—rather than on more aggressive systems targeting the hard-core nonuser. The functional characteristics of these reminder systems have already been described in an earlier section. The manufacturers, however, recognized that a number of design decisions were made without the benefit of empirical human performance data, which—if available—might increase both effectiveness and acceptability. For example, the optimal loudness of the reminder’s chime has not been determined, nor has its relation to other in-vehicle warning and information systems, which have been proliferating in recent years. It is well known that human attention and information-processing capacities are limited (Wickens 1991; Kahneman 1973), so the effectiveness of any belt reminder system (and its impact on other aspects of driver performance) must be considered within the context of the overall stimulus and task environment. According to the manufacturers, many such issues, which have not been resolved in the first generation of enhanced belt reminder systems, merit careful study as field evidence accumulates. The companies were unable to provide systematic field information concerning the effectiveness of the new enhanced belt reminders, which reflects the recent entry of the technologies into the market. In fact, one company suggested that NHTSA should take responsibility for collecting data on the effectiveness of different enhanced belt reminder systems in getting motorists to buckle up, particularly those involved in crashes. Manufacturers’ Market Research The manufacturers who briefed the committee provided some limited company-sponsored market research on consumer acceptability of

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Buckling Up: Technologies to Increase Seat Belt Use enhanced belt reminder systems. At the December committee meeting, General Motors reported the results of clinics of approximately 1,000 consumers conducted in California in 1999 to gather data on belt use habits and the perceived effectiveness and desirability of current and enhanced belt reminder systems. Forty-nine percent of the respondents reported that the current NHTSA-required 4- to 8-second reminder helps them remember to wear their seat belts. Eighty-one percent indicated interest in an enhanced belt reminder system for the driver and front-seat occupants. Seventy-one percent thought that the systems should be extended to rear-seat occupants, particularly drivers of sport utility vehicles (SUVs) and vans who frequently transport children and find it difficult to see whether their children are buckled up. Yet, only 35 percent reported that they wanted a rear-seat belt reminder system in their next vehicle. After the December meeting, a January 2001 Ford Motor Company telephone survey of approximately 1,200 owners of Ford passenger cars, SUVs, vans, and pickup trucks—with and without the Ford BeltMinder—was made available to the committee. The purpose of the survey was to obtain customer feedback on the new technology. Ninety percent or more of owners of the Taurus/Sable, Lincoln LS, Ranger, Explorer Sport Trac, Excursion, and Econoline reported that they were completely satisfied with the BeltMinder. Approximately three-quarters of Focus/Cougar, Mustang, and Explorer Sport owners reported being completely or somewhat satisfied with the system (Ford Motor Company and Global Consumer Insights 2001, 5).10 Eight in 10 BeltMinder owners indicated that they would purchase a vehicle with a belt reminder in the future. More than 7 in 10 would recommend the BeltMinder to other drivers, and almost 90 percent of Ford drivers with the BeltMinder want the system for their passengers (Ford Motor Company and Global Consumer Insights 2001). Female and older drivers (i.e., over 50) scored higher than male or younger drivers on satisfaction with the BeltMinder, interest in buying it again, and recommending it to others. 10 Respondents were asked to report their satisfaction with the BeltMinder on a five-point scale, ranging from “completely satisfied” to “very dissatisfied.”

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Buckling Up: Technologies to Increase Seat Belt Use U.S. Research Studies Only two studies that provide an assessment of the effectiveness and acceptability of enhanced belt reminder systems in the U.S. market could be found in the literature. The lack of studies is not surprising in view of the limited commercial availability of these systems. The first study, conducted by the Insurance Institute for Highway Safety (IIHS) in cooperation with Ford Motor Company, provided an initial evaluation of the Ford BeltMinder and found preliminary evidence that the technology is encouraging increased belt use (Williams et al. 2002). Researchers unobtrusively observed belt use among drivers of vehicles brought in for service at 12 Ford dealerships in Tulsa and Oklahoma City, Oklahoma, in August and September 2001. Overall, seat belt use rates were 76 percent for drivers in vehicles equipped with the BeltMinder compared with 71 percent for drivers of late-model Fords without the reminder system—a statistically significant 7 percent gain (Williams et al. 2002, 295).11 No follow-up studies have been conducted at other locations to determine whether these results can be replicated. The second study, also conducted by IIHS just before completion of this committee’s work, involved in-person interviews with 405 drivers of Ford vehicles with BeltMinder systems at five Ford dealerships in the metropolitan Boston area in March and April 2003 (Williams and Wells 2003). Ford Motor Company facilitated the study, but it was made clear to potential respondents that the research was being conducted independently. Approximately two-thirds of the 405 drivers interviewed reported that they had experienced the reminder system one or more times when they had neglected to buckle up. Seventy-three percent reported that they buckled up the last time this happened, and 46 percent of all respondents said that their belt use had increased since driving a vehicle with the BeltMinder (Williams and Wells 2003, 6, 10). These positive reports provide further evidence in support of the earlier observational study that the BeltMinder is increasing belt use. The system also appears to be acceptable to drivers. Seventy-eight percent of those interviewed said they liked the system. Seventy-nine percent reported that they would like a similar device in their next vehicle (Williams and Wells 2003, 1). 11 The difference reflects a 5 percentage point gain in belt use but a 7 percent increase [i.e., (76 –71)/71=0.07].

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Buckling Up: Technologies to Increase Seat Belt Use 35 respondents (Bentley et al. 2003, 10).16 Participants for both types of activities were recruited by random digit dialing. No specific attempt was made to represent the demographic characteristics of the areas. The participants in both the in-depth interviews and the focus groups were exposed to four seat belt use technologies—two belt reminder systems and two interlock systems—reflecting technologies of increasing intrusiveness (see Figure 4-1 and Box 4-3 for system descriptions). The belt reminder systems were presented in the form of two short video clips; the interlock systems were described on two storyboards.17 Initially, the respondents discussed their opinions about seat belts and the reasons and circumstances affecting their use (see Chapter 2 for results). Then they were asked to rate the technologies, using a five-point scale, on both the effectiveness and the acceptability of each of the four devices.18 (The order of presentation was rotated in a counterbalancing scheme to prevent order effect bias.) After commenting on each technology, the respondents were asked to rank order the four devices from one to four in terms of their relative effectiveness and acceptability.19 Finally, the respondents were asked whether the technologies should be mandated (Bentley et al. 2003, 12). The results of the NHTSA report do not provide quantitative results that can be subjected to meaningful statistical analysis for generalization to the entire automobile-buying population (Bentley et al. 2003, 12). Nevertheless, the findings provide useful qualitative information about consumer reactions to new technologies designed to increase belt use. The results that follow were developed by the committee from the original responses to the interview and focus group questions and do not appear in the NHTSA report. 16 Focus group participants were asked to rate and rank the technologies individually and write their responses on a worksheet. Only then did they discuss their individual responses with the group. 17 Reactions may have been different if the participants had been able to drive in vehicles equipped with the technologies, but time and resource constraints precluded this option. Human subjects’ protection was also an issue, because participants would have had to drive unbelted to experience the reminder systems. 18 The scale for effectiveness ranged from “very effective” to “not at all effective.” The scale for acceptability ranged from “very acceptable” to “not at all acceptable.” 19 Responses to the ranking data were not considered reliable and hence were not included in this report. Several respondents were unable or unwilling to rank order the devices, ranking either some or all of them equivalently. For example, this was the case for approximately 10 percent of the rankings on acceptability. Without a better understanding of the respondents’ intent, it was believed that these responses would skew the overall results.

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Buckling Up: Technologies to Increase Seat Belt Use Figure 4-1 Seat belt use technologies arrayed by level of intrusiveness. Results Table 4-1 and the tables in Appendix B provide a summary of respondent ratings of the four technologies’ effectiveness and acceptability. The results are first provided for all 141 respondents.20 Then they are examined by user group (35 full-time users, 89 part-time users, and 17 hard-core nonusers), gender, age, and location (see Table B-1). Overall Ratings A much higher percentage of the respondents rated each of the technologies “effective” than “not effective” (ranging from 20 The respondents were asked to rate the effectiveness and acceptability of the technologies on a five-point scale. The ratings presented in this report range from “one” (least) to “five” (most) effective and acceptable. In Table 4-1, the ratings were further combined into three-point scales (combining “very effective” with “effective” and “very ineffective” with “ineffective,” with similar combining of the acceptability scales) to provide greater contrast between positive and negative results. The responses for each of the five ratings can be found in Appendix B, Table B-2. Because of small sample sizes, only the mean rating was provided for responses analyzed on the basis of gender, age, and location (see Table B-3).

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Buckling Up: Technologies to Increase Seat Belt Use Box 4-3 Seat Belt Use Technology Concepts Tested (Bentley et al. 2003, 8–9) Intermittent chime and flashing symbol (Ford BeltMinder-type system) The current standard 4- to 8-second reminder appears when the driver turns on the ignition. When the driver exceeds 3 mph (4.8 km/h), a flashing light and chime appear for 6 seconds. After 6 seconds the flashing light and chime cease. This cycle is repeated every 30 seconds for 5 minutes. Continuous chime and flashing symbol connected to the speed of the vehicle (Saab prototype) When the driver turns on the ignition, a symbol appears on the dashboard indicating that someone in the car is not wearing a safety belt. Another symbol on the dashboard indicates who is unbuckled; in the case of the video presentation it was the driver. When the driver reaches about 9 mph (14.5 km/h), an audio warning sounds (one ping) and a warning light starts to flash. At about 15 mph (24 km/h), the audio signal starts to ping continuously along with the flashing symbol. At about 30 mph (48 km/h), the light and audio warnings reach their maximum frequency. As the driver slows down, so do the warnings, and when the vehicle stops the signals stop. When the driver accelerates again, the audio and visual warnings resume at their highest frequency. When the driver buckles up, the warnings cease. If for any reason the driver unbuckles while the vehicle is moving, the warning light reappears and a warning signal sounds (one ping). After 15 seconds, the symbol begins to flash and the audio warning starts to ping continuously, and after 30 seconds the reminders reach their highest frequency.

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Buckling Up: Technologies to Increase Seat Belt Use Entertainment interlock The standard 4- to 8-second reminder appears after the driver starts the ignition. However, the vehicle stereo does not work until the driver buckles up. Transmission interlock The standard 4- to 8-second reminder appears after the driver starts the ignition. However, the vehicle cannot be shifted into gear until the driver buckles up. 61 to 88 percent). A higher percentage of respondents also rated the two reminder systems (Ford and Saab) “acceptable” than “not acceptable” (71 percent and 56 percent, respectively). However, this result did not hold for the interlock systems, which somewhat more respondents found not acceptable than acceptable (see Table 4-1). Anecdotally, several respondents, generally hard-core nonusers, indicated that the devices were acceptable but not effective because they believed they could circumvent them—for example, by drowning out the sound of the chime with the radio—or disable them entirely (Bentley et al. 2003, 4, 14). These responses obfuscate interpretation of the ratings. Of the two reminder systems, respondents were more likely to rate the Ford BeltMinder as acceptable (71 percent versus 56 percent for the Saab system) but were also somewhat less likely to rate it effective compared with the more insistent Saab system (78 percent versus 83 percent) (Table 4-1). The transmission interlock was most likely of all the devices to be rated effective—88 percent rated it effective. However, only 43 percent of the respondents rated it acceptable. A somewhat lower percentage of respondents (37 percent) rated the entertainment interlock acceptable. However, 40 percent rated that device as either not effective or neutral (Table 4-1). Follow-up questions found that the effectiveness of the entertainment interlock depended largely on the extent to which drivers use their stereo systems (Bentley et al. 2003, 14).

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Buckling Up: Technologies to Increase Seat Belt Use Table 4-1 Analysis of Ratings from NHTSA In-Depth Interviews and Focus Groups by Technology, Overall and by User Group (Percentage) Reported Acceptability Reported Effectiveness   Ford Saab Entertainment Interlock Transmission Interlock   Ford Saab Entertainment Interlock Transmission Interlock Overall (N = 141)                   Not acceptable 15 27 45 45 Not effective 12 10 27 8 Neutral 14 16 18 11 Neutral 9 7 13 4 Acceptable 71 56 37 43 Effective 78 83 61 88 Full-Time Users (N = 35)                   Not acceptable 3 28 51 55 Not effective 0 9 34 3 Neutral 3 11 29 14 Neutral 0 6 14 0 Acceptable 94 60 20 32 Effective 100 86 52 97 Part-Time Users (N = 89)                   Not acceptable 16 22 41 37 Not effective 14 9 24 10 Neutral 20 18 15 11 Neutral 12 7 14 2 Acceptable 64 60 45 52 Effective 74 84 63 88 Hard-Core Nonusers (N = 17)                   Not acceptable 35 53 53 71 Not effective 30 18 30 6 Neutral 0 12 12 6 Neutral 12 12 6 18 Acceptable 64 36 35 24 Effective 59 70 65 77 NOTE: “Not acceptable” is the sum of ratings “very unacceptable” and “unacceptable” (1 and 2); “acceptable” is the sum of ratings “very acceptable” and “acceptable” (4 and 5). “Not effective” is the sum of ratings “very ineffective” and “ineffective” (1 and 2); “effective” is the sum of ratings “very effective” and “effective” (4 and 5). The percentages may not add to 100 because of rounding. See Table B-2 for a more detailed breakdown by rating category.

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Buckling Up: Technologies to Increase Seat Belt Use With the exception of the entertainment interlock, the higher the effectiveness rating for a device, the lower the acceptability rating. This was most pronounced for the transmission interlock—88 percent rated the transmission interlock effective but only 43 percent rated it acceptable. Ratings by User Group The responses of different user groups, especially part-time users, were of particular interest to the committee because they are the primary group to which the technologies are directed. Nearly two-thirds of part-time users rated the belt reminder systems acceptable (64 percent for the Ford BeltMinder and 60 percent for the Saab system). The reminder systems also were likely to be rated effective (74 percent for the Ford BeltMinder and 84 percent for the Saab system). Approximately twice as many part-time users, however, rated the interlocks unacceptable compared with the reminder systems (Table 4-1). Nevertheless, part-time users were more likely to rate the interlocks as acceptable than other user groups. Of the much smaller group of 17 hard-core nonusers, fewer were likely to rate the more aggressive technologies—the Saab belt reminder and the transmission interlock—as acceptable compared with the other groups. For example, only 36 percent rated the Saab system acceptable (Table 4-1). And the hard-core nonusers were the most likely of any user group to rate the transmission interlock as unacceptable, with 71 percent rating it not acceptable. Not surprisingly, hard-core nonusers were more likely to give the Saab reminder and the transmission interlock high effectiveness ratings compared with the other two technologies, 70 percent and 77 percent, respectively. The particularly negative reaction to the transmission interlock from hard-core nonusers stemmed in part from their belief that this device infringes on an individual’s right to choose whether to buckle up (Bentley et al. 2003, 15). However, a relatively high percentage (55 percent) of full-time users also rated the transmission interlock not acceptable. This group did not like systems that affect the operability of the vehicle, nor were they sympathetic to the idea of having an intrusive device in their vehicle just because others do not buckle up (Bentley et al. 2003, 34).

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Buckling Up: Technologies to Increase Seat Belt Use Ratings by Gender, Age, and Location Mean ratings are provided by gender, age, and location (Table B-3). Because of small sample sizes, no attempt was made to break down the data further by rating category (e.g., acceptable, neutral, not acceptable) as was done in Table 4-1. The mean effectiveness and acceptability ratings are higher for females than for males and for the oldest age group than for the youngest age group for all technologies except the entertainment interlock. Males and the two youngest age groups rated the entertainment interlock more effective than did females or the oldest age group, which probably reflects greater use of the stereo system by these groups. However, none of the age groups rated the entertainment interlock very highly on acceptability. Mean acceptability ratings for reminder systems were higher than for interlocks for all three locations. This pattern did not hold for mean effectiveness ratings, mainly because the transmission interlock was rated most effective in all locations. Mandating Seat Belt Use Technologies Respondents were asked whether they agreed that reminder systems and interlocks should be required in vehicles. If they responded positively, they were then asked whether the federal government should mandate this. Quantitative results were not available for these questions, but a summary of the responses provided in the NHTSA report suggests that most participants were supportive of the idea of mandating seat belt reminder systems and interlocks (Bentley et al. 2003, 38). Although many stated that mandates for reminders were acceptable, some thought that requiring interlocks was not. These devices were considered to be excessive in their attempt to control driver behavior and limit freedom of choice (Bentley et al. 2003, 38). Some hard-core nonusers were against mandates altogether. They believed that wearing a seat belt is a matter of personal choice that should not involve government intervention (Bentley et al. 2003, 15). SUMMARY OF THE STATE OF KNOWLEDGE Nearly 30 years after NHTSA was prohibited from requiring seat belt interlock systems or continuous buzzer reminders longer than 8 seconds in duration, the automobile manufacturers are voluntarily introducing

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Buckling Up: Technologies to Increase Seat Belt Use enhanced seat belt use technologies in passenger vehicles. Ford Motor Company started the move toward a new generation of enhanced belt reminder systems with the introduction of the Ford BeltMinder on selected MY 2000 vehicles. Enhanced belt reminder systems are also being introduced in Europe, where belt use rates are higher, and incentives are being offered to manufacturers through the EuroNCAP program to improve vehicle consumer safety ratings by providing systems that meet certain performance criteria. No automobile manufacturer, either in the United States or abroad, is providing vehicles with interlock systems as original equipment, targeted to the general consumer. However, a seat belt shifter lock is being developed for special fleets and aftermarket applications in the United States. Because enhanced seat belt use technologies are so new, few studies of their effectiveness have been conducted. Nevertheless, the available evidence suggests that consumers generally find new belt reminder systems somewhat successful in convincing part-time users—the largest nonuser group—to buckle up. For example, the initial IIHS study (Williams et al. 2002), which was limited to two locations in Oklahoma, observed a statistically significant 7 percent increase in seat belt use by drivers in passenger vehicles equipped with the Ford BeltMinder compared with drivers of nonequipped late-model Fords. A subsequent IIHS study corroborated these findings. In interviews in Boston with drivers of BeltMinder-equipped Ford vehicles, overall, two-thirds reported that they had activated the system. Of these, approximately three-fourths buckled up and nearly half of all respondents said their belt use had increased. Results were encouraging for part-time belt users. More than four-fifths of this user group had activated the system at least once, 70 percent fastened their belts in response, and approximately 75 percent said their belt use had increased. No studies of the effectiveness of new European belt reminder systems could be found. Information on consumer acceptability of seat belt use technologies from the manufacturers, the recent IIHS study, and the NHTSA interviews and focus groups conducted for the present study suggest a generally positive response to enhanced belt reminder systems. For example, nearly two-thirds of self-reported part-time users rated

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Buckling Up: Technologies to Increase Seat Belt Use reminder systems acceptable in the NHTSA interviews. As a general rule, the more intrusive the system, the less acceptable it is. This finding was particularly pronounced for the transmission interlock, which, of the four technologies, was most likely to be rated effective by all user groups who participated in the NHTSA interviews and focus groups, but was less likely to be rated acceptable across the board than reminder systems. Self-reported hard-core nonusers who participated in the NHTSA interviews were more likely to be opposed to all systems than other user groups, with the exception of the Ford BeltMinder, which two-thirds of hard-core nonusers found acceptable, as was the case for part-time users. However, as the earlier IIHS study noted, acceptance does not necessarily lead to increased belt use, particularly for hard-core nonusers. More intrusive technologies may be required to convince this group to buckle up. In sum, the data available to date provide strongly converging evidence in support of both the potential effectiveness and consumer acceptance of many new seat belt use technologies, particularly enhanced belt reminder systems. Despite limitations in the individual studies, surveys, and other pieces of evidence that are spelled out in the present report, the fact that findings from such a diverse set of information sources converge on this core conclusion is extremely important. However, much remains to be learned. Fortunately, larger numbers of belt reminder systems will soon be introduced in the marketplace. With characteristics that vary across manufacturers in the loudness, urgency, and duration of their chime and light components, these systems provide a natural laboratory for study. Key knowledge gaps remain concerning the design, effectiveness, and acceptability of enhanced belt reminders. For example, unresolved design issues include the optimal loudness of the reminder’s chime and its relation to other warning and information systems. Temporary muting of nonessential systems (e.g., radio, CD player) could be considered so that drivers do not drown out the chime. Appropriate design of disconnection systems is also likely to influence both the effectiveness and the acceptability of belt reminder systems. Finally, because of the benefits of rear-seat belt use, resolution of tech-

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Buckling Up: Technologies to Increase Seat Belt Use nical problems hindering the installation of rear-seat belt reminder systems is important, especially as the cost of sensors for the rear seats declines. More comprehensive studies of the effects of reminder systems on belt use need to be conducted. Comparative studies of the effectiveness of aggressive belt reminder systems would be helpful in determining whether they can provide additional gains in belt use, particularly among the hard-core nonuser groups. Finally, more data are needed on consumer acceptance. For example, although initial reactions toward interlock systems were negative, several of their undesirable features (e.g., inability to play the radio when the vehicle is not in motion) could be engineered out. As more consumers actually experience the systems, attitudes may differ from those expressed in interviews, where respondents could only be given general explanations or visual presentations of how the systems work. The converging evidence of the effectiveness and consumer acceptance of enhanced belt reminder systems is favorable. In the next chapter, potential statutory and regulatory impediments to their installation are addressed. REFERENCES Abbreviations ACTS Automotive Coalition for Traffic Safety, Inc. IIHS Insurance Institute for Highway Safety ACTS. 2000. ACTS Telephone Surveys of Drivers, Seat Belt Users and Non/Part-Time Users. Nov. Bentley, J. J., R. Kurrus, and N. Beuse. 2003. Qualitative Research Regarding Attitudes Towards Four Technologies Aimed at Increasing Safety Belt Use. Report 2003-01. Equals Three Communications, Inc., Bethesda, Md., June. Bylund, P., and U. Björnstig. 2001. Use of Seat Belts in Cars with Different Seat Belt Reminder Systems. A Study of Injured Car Drivers. In 45th Annual Proceedings, Association for the Advancement of Automotive Medicine, San Antonio, Tex., Sept. 24–26, pp. 1–9. Dahlstedt, S. 1999. Non-Users’ Motives for Not Wearing the Seat Belt. VTI Rapport 417. Swedish National Road and Transport Research Institute, Linkoping, Sweden. DeYoung, D. J. 2002. An Evaluation of the Implementation of Ignition Interlock in California. Journal of Safety Research, Vol. 33, No. 4, Winter, pp. 473–482. Fildes, B., M. Fitzharris, S. Koppel, and P. Vulcan. 2002. Benefits of Seat Belt Reminder Systems. Report CR 211. Monash University Accident Research Centre, Victoria, Australia, Dec. Ford Motor Company and Global Consumer Insights. 2001. Belt Minder Awareness and Satisfaction Research: U.S. Market. March.

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Buckling Up: Technologies to Increase Seat Belt Use Harrison, W. A., T. M. Senserrick, and C. Tingvall. 2000. Development and Trial of Method to Investigate the Accceptability of Seat Belt Reminder Systems. Report 170. Monash University Accident Research Centre, Victoria, Australia. IIHS and Traffic Injury Research Foundation. 2003. Graduated Licensing: A Blueprint for North America. Arlington, Va., and Ottawa, Ontario, Canada, April. Kahneman, D. 1973. Attention and Effort. Prentice-Hall, Englewood Cliffs, N.J. Lawrence Research. 2000. A National Survey of Licensed Drivers Age 16 and Older. Automotive Coalition for Traffic Safety, Inc., Nov. Voas, R. B., K. O. Blackman, A. S. Tippets, and P. R. Marques. 2002. Evaluation of a Program to Motivate Impaired Driving Offenders to Install Ignition Interlocks. Accident Analysis and Prevention, Vol. 34, No. 4, July, pp. 449–455. Wickens, C. D. 1991. Processing Resources and Attention. In Multiple Task Performance (D. Damos, ed.), Taylor and Francis, London, pp. 1–34. Williams, A. F., J. K. Wells, and C. M. Farmer. 2002. Effectiveness of Ford’s Belt Reminder System in Increasing Seat Belt Use. Injury Prevention, Vol. 8, pp. 293–296. Williams, A. F., and J. K. Wells. 2003. Drivers’ Assessment of Ford’s Belt Reminder System. Traffic Injury Prevention (in press).