Effects of Radio Tuning on Driving Performance - CiteSeerX

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PROCEEDINGS of the HUMAN FACTORS AND ERGONOMICS SOCIETY 47th ANNUAL MEETING—2003

EFFECTS OF RADIO TUNING ON DRIVING PERFORMANCE Mustapha Mouloua, Peter A. Hancock, Edward Rinalducci, and Christopher Brill University of Central Florida Orlando, Florida This paper introduces some of the research work on the effects of telematics, in this case a radio system, on driver’s performance. Twenty-four undergraduate students participated in a series of simulated driving scenarios. In the pre- and post-allocation phases, all participants were required to drive two-four minute phases to establish their baseline scores. In the allocation phase, they were required to tune to a series of local radio stations while performing the same driving scenarios. The results indicated that participants committed more driving errors and violations during the radio-tuning phase than any of the other pre- and post-allocation phases. These errors were manifested in an increased number of crossing the median marking, leaving the roadway, and/or lane deviation. The implications of these results are also outlined in the present paper. INTRODUCTION There are numerous sources of driver distractions that can negatively affect a driver’s performance. These distractions have been documented in research surveys as well as police reports of traffic incidents. Many states have identified driver distraction as one of the driver-related contributing causes of collision (e.g., Florida has.just added driver distraction in the crash report in January of 200 1). Driver distractions cover a range of activities from a person driving a car while attempting to light a cigarette, apply make-up, eat or drink, tune the radio, use a cellular phone or an in-vehicle navigation system. Of particular present interest are the distracting effects of telematics that include traffic information, telecommunications,intelligent aiding and control, and navigational systems. These devices are now found on-board various U.S. and foreign automobiles. There are many benefits of telematics but there remain numerous behavioral problems resulting from poor use and poor design of these devices. Telematics are intended to enhance drivers’ safety, increase wayfinding performance, and minimize travel time and distance. Cell phones and many of the in-vehicle navigation systems have a safety feature that can help locate a stranded or incapacitated driver and offer assistance if needed. Radio communication can alert a driver to caution or provide information on how to avoid a hazardous traffic area while driving. Telematics have many features that can serve to increase driver’s safety, yet they can also increase driver distraction, and thus diminish safety. The consensus of current findings indicate that cell phone use has adverse effects on driver reaction time, mental workload, vehicle lane position and response time to crucial driving demands (Hancock, Lesch, & Simmons, 2002). Across all cell phone types (hand-held versus hands-free), it is evident that performance degrades, indicating that hands-free does not equal risk free. Research comparisons of hand-held and handsfree phones show that there is little difference in risk during the act of conversation due to the continued presence of a mental distraction. In comparing mobile phone use with other in car activities, Violanti and Marshall (1996) found that mobile phone use was most distracting if used for more than

fifty minutes per month. Considering the physical and mental activity required by mobile phone users, it appears that this activity is one of the most distracting activities that is possible to carry out while driving. In contrast, McKnight and McKnight (1 993) found mobile phone use to be no more dangerous than tuning the radio. However, even if cell phones are only as distracting as tuning a radio, the actual exposure to accident risk is significantly higher due to the greater lengths of time spent on the phone compared to the discrete, one time act of tuning the radio. The type of conversation is significant in determining crash risk. Violanti and Marshall (1996) found that cellular phone users engaging in intense or business conversations were more at risk to have a crash. Moreover, McKnight and McKnight (1993) found that complex conversationswere the most dangerous phone-related activity. The general finding that engaging in a simple conversation is relatively risk-free compared to engaging in an intense conversation has been confirmed by other studies (McKnight & McKnight, 1991; 1993). A possible explanation for this effect is given by Alm and Nilsson (1 995), whereby phone use and driving are parallel tasks competing for the drivers attention. If both the driving task and phone task are simple, the driver can easily accommodate one or the other. However, if either is difficult, a resource competition induces performance decrement (see Alm & Nilsson, 1995). Srinivasan and Jovanis (1 997) used a fixed-base, high fidelity simulator to examine the differential effects of five invehicle route guidance systems (paper map, head-down turnby-turn display, head-down electronic route map, head-up turn-by-turn display, and audio guidance system). The results showed that participants responded the fastest with audio and the slowest with the paper map. Streeter, Vitello, and Wonsiewics (1 985) tested participants on four different systems (taped instructions, customized route maps, taped instructions and customized route maps, and a control condition). The audio system provided information on distance to the turn, direction of turn, turn street name, and landmarks. The customized route maps were four-color schematic maps showing the route to be traveled in red. The control group was given one of the two New Jersey maps and

PROCEEDINGS of the HUMAN FACTORS AND ERGONOMICS SOCIETY 47th ANNUAL MEETING—2003

an address and was instructed to find their way as they wished. The results indicated that participants in the audio group took the least time and drove the least distance in reaching the destination, as well as the least number of errors. Participants in the audio-plus-map condition performed the worst, a result that may be due to information overload. Clearly each of the previously mentioned studies, and others in the literature, indicate that driving performance can be degraded by the use of such in-vehicle systems, which present real-world distractants. However, with one possible exception, that being the gap assessment task in the study by Brown et al. (1969), performance requirements have not been evaluated at critical phases of driving but rather in very benign conditions. It should be noted here that the three extant studies using test-track facilities are now rather dated. The study by Brown and his colleagues is now three decades old and even the study by Zwahlen et al. (1988) was conducted before the major ITS initiatives focused such a great degree of effort on the area of in-vehicle technologies. Since those experiments there have been major changes in technology. These changes occur not simply in the vehicles under examination, but especially in the size and capability of technologies,’such as cellular phones, which mean that re-evaluation of contemporary systems is vital (Hancock et al., 2002). One of our on-going concerns is centered on an understanding of safety (Hancock & Scallen, 1999). Since, in general,.driving is not an overloading task, drivers can and do successfully perform subsidiary tasks and rapidly habituate to dual tasking in the driver’s seat. Risks, and its cousin safety, thus vary with the degree to which the driving task is merely satisfied (under normal conditions) or rather needs to be optimized (under the momentary challenge of critical events). Our thematic concern is distraction at these crucial points in time, although data from more normative phases of performance can confirm this search. Our present study was designed to examine and investigate one aspect of driver distraction-radio tuning- and its deleterious effects on drivers’ performance. We hypothesized that radio tuning would degrade driver performance and increase workload. METHOD Participants Twenty-four undergraduate students acted as participant drivers in this study. They were recruited from local psychology classes and were given extra credit for their participation. All participants were tested and shown to have 20140 vision or better, following Florida DMV guidelines. Participants of all ages and ethnicity were used to allow for variability in our predictors. The participants were treated in accordance with the “Ethical Principles of Psychologists and Code of Conduct” (American Psychological Association, 1992).

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Materials and Apparatus The simulation package for the present work was Microsoft’s Midtown Madness. Display features included the speedometer and the tachometer, which were embedded in the dashboard on the lower third of the screen and a rearview mirror in the upper right hand comer of the screen. The program allowed manipulation of a simulated driving experience through the city of Chicago with common roadway obstacles, including traffic density and pedestrians. A force feedback steering wheel and pedals were used for the driver inputs. He experimental set-up is illustrated in Figure 1. A modified perimeter made of opaque black paneling incorporated a 2 1” Sony Trinitron SVGA monitor and an AM/FM Linear Research analog tuner located 18” to the right of the steering wheel. Participants were seated in front of the monitor and adjusted their position to an appropriate distance from the pedals and steering wheel, simulating their normal driving posture. An Exxis closed-circuit video camera was positioned 6” above the monitor to videotape the participant’s face and another was fixed to the 8’ ceiling, 2’ behind the participant’s right shoulder in order to videotape the simulation area. The video monitor displaying the closed circuit video camera output was located in an adjacent room. Additionally, driving tasks were timed to ensure standardization of driving phases.

Procedure Upon arrival to, all participants were greeted by the experimenter and asked to read and sign an informed consent form. Participants were randomly assigned to a condition before their arrival. They were then asked to position themselves comfortably in front of the driving apparatus. The driving instructions, to explore the city and obey all traffic laws, including 45 mph in-city and 55 mph highway speed limits, were read aloud by the experimenter. Low and moderate traffic densities were used as a between-subject condition. Participants were given four minutes to familiarize themselves with the driving apparatus. Before beginning the next phase of driving, participants were shown how to operate the radio. Driving instructions were read for the second time before participants were instructed to begin driving. After four minutes, participants were asked to turn on the radio and tune to a series of local FM stations over the next four minutes while continuing to drive. At the eight-minute mark, participants were instructed to turn the radio off and to continue the driving task for an additional four minutes. The experimenters reviewed each participant’s taped driving for post performance data coding. Experimenters had specific guidelines as to how to score behaviors including lane deviations, defined as the car partially crossing into a same-direction lane; median crossings, defined as the car crossing into oncoming traffic; leaving the road and crossing the right shoulder; violating the speed limit; car accidents; failing to stop at lights and stop signs; and damaging the vehicle.

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PROCEEDINGS of the HUMAN FACTORS AND ERGONOMICS SOCIETY 47th ANNUAL MEETING—2003

RESULTS The results indicated that the radio-tuning task had a significant effect on five of the six dependent variables. A 2 (traffic condition: low vs. moderate traffic) x 3 (time: before, during, or after radio-tuning task) repeated measures ANOVA revealed that there was a significant main effect for traffic condition [F(1,19) = 4 . 9 3 , ~ = .039] and time [F(2,38) = 13.7,p < .0005] on the number of lane deviation errors. Results indicated that participants made significantly more lane deviation errors during the 4-minute period involving the radio-tuning task ( M = 8.6, SD = 6.0) than in the 4 minutes before ( M = 2.7, SD = 2.1) or after it ( M = 3.5, SD = 3.4). Furthermore, participants made significantly more mistakes during the radio-tuning task if they were in the low traffic condition ( M = 10.9, SD = 7.4) than in the moderate traffic condition ( M = 6.0, SD = 2.4). An additional 2 by 3 repeated measured ANOVA indicated that there was a significant main effect for time (before, during, or after radio tuning task) on the number of errors crossing the median [F (2,38) = 3.96, p = .03]. As depicted in Figure 1, participants made significantly more errors crossing the median duriig the radio-tuning task ( M = 2.8, SD =2.9) than either before (M-= 1.2, SD = 1.4) or after the radio-tuning phase ( M = 1.3, SD = 1.7). There was no significant main effect for traffic condition [F (1,19) = .114,p = .740]. Figure 1. Mean number of Median Crossing Errors. 3.0

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Traffic Condition

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Results also revealed that there was a significant main effect for time (before, during, or after radio tuning task) on the number of leaving the road errors [F (2,36) = 4.43, p = .O 191. Participants made significantly more leaving-the-road errors during the radio-tuning task ( M = 2.0, SD= 2.1) than before ( M = 3 1 , SD = 1.2) or after ( M = 1.6, SD = 2.0). There was no significant main effect for traffic condition [F (1,18) = .457, p = .507]. The analysis also revealed that there was a main effect for driving phase on the number of traffic accidents participants were involved in [F (2, 38) = 3.62, p = .037]. The number of traffic accidents was significantly higher during the 4-minute

radio-tuning task ( M = 1.2, SD= 2.6) than the 4 minutes before ( M = .09, SD = .43) or after ( M = .42, SD = .93) the radiotuning task. Lastly, a significant main effect for time on participants’ speed limit [F (2,38) = 4.33, p = .02)]. Participants were more likely to disobey the instructed speed limit (e.& driving either at a higher or lower speed than the instructed speed limit) during the radio-tuning task ( M = 1.29, SD = 1.45) than before ( M = .38, S = .59) or after it ( M = .71, SD = .90). DISCUSSION The present findings indicate that radio systems are indeed capacity demanding. The distraction task results demonstrate the increased level of workload associated with the radio devices. In addition, driving performance errors were also higher when the participants were engaged in radio tuning tasks. These findings suggest the need to regulate the use of devices such as Radio and CD systems, which are commonly found in automobiles. These systems tend to overload the driver’s capacity for attention, especially if the driver is still novice. Although these initial results were obtained with a low fidelity-driving simulator, more experimental studies are currently underway to validate these results with a more advanced and full-motion driving simulator. The results will have major implications for transportation safety and the design of telematics, range of telematic devices, and or a high fidelity simulator. This would allow greater generalization. Overall, the study revealed a larger number of lane deviation errors, drivers leaving the road, drivers crossing the road, and drivers crossing the median while the distracter task was in effect. Both the cell phone use and radio-tuning task were associated with poorer driving performance and increased workload when compared to the initial driving task. The dependent variable of lane deviations was recorded as being more frequent d&ing the radio-tuning task than in the cell phone simulation. This finding suggests that, consistent with our hypothesis, the activity of manually tuning an analog radio car radio causes a greater amount of distraction to the driver than did cell phone usage. As expected the distracter task caused driving performances to decline a significant amount in most areas. Drivers also reported a higher level of workload, stress, and frustration during the initiation of the distracter task. The driving errors that were not significant were collisions and the failure to stop at stop indicators. These errors, which require short-term processing and reaction, may evoke more attention for safety and are more discrete than the monotonous act of staying within a lane. Findings of this study may be limited due to sample size so future studies should make efforts to increase the number of participants to ensure the reliability and validity of the findings. Further research on driving performance and telematics should include a more diverse pool of electronic devices to gain a better understanding of the complex nature of the interaction between driving performance and the additional workload accompanying modem technology.

PROCEEDINGS of the HUMAN FACTORS AND ERGONOMICS SOCIETY 47th ANNUAL MEETING—2003

General Conclusions Many researchers in the driving community are engaged in a common search for methods and techniques with which to assess the impact of emerging in-vehicle devices. One fundamental barrier faced by all such researchers is that we still do not have a good basic model of normative driving and without this baseline it is more than problematic to assess performance changes. What is required is some form of ‘figure of merit’ that combines the baseline elements of momentary vehicle control with those more strategic decisions, e.g., route selection, to provide a fundamental and agreed base measure against which to compare all candidate technologies. The results of the simulation experiments suggest that when tuning a radio more errors are made than before or after, because of the distractive power of the task (in either a low or moderate traffic condition). It is clearly evident that any distracter task, such as tuning a radio, produces a performance decrement. This decrement is translated into errors of lane deviations, crossing the median, leaving the road, the number of traffic accidents, as well as a failure to follow the designated speed limit. The results clearly indicate that the secondary task was a robust measure or workload and driver distraction. The effects of telematics were very pronounced and caused a distinct degradation in the secondary task performance. Also, this effect is contingent upon the type of telematics used. Practical Implications and Guidelines Based on these findings, it is recommended that drivers be aware of the deleterious effects of these technologies on driver distraction, performance, and safety. Our conclusion indicates that it is important to seriously consider not using any telematic device such as a radio/CD system or cell phone while the car is in motion under heavy traffic congestion, poor weather and/or road conditions, or unfamiliar areas. Novice drivers should also not use a telematic device until they reach a proficiency level allowing them to drive more comfortably. Older drivers who may be at a disadvantage in their cognitive and sensory skills should also limit the use of these devices only to safe situations. We suggest that the industry and manufacturers be responsible in evaluating their products before marketing them. This evaluation should take place in accordance with existing research data, human factors standards, and usability testing procedures. The following is a list of recommendations regarding driver distraction associated with the use of telematics that we have investigated in our study: 1. Consider tuning the radio/CD only if the traffic condition is not very high and when the vehicle is fully stationary.

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2. Consider using radio/CD systems equipped with voice activation systems in order to minimize extensive corporal movements while driving. 3. Consider using radio/CD systems that are hlly integrated within the steering wheel system. There are several systems that can activate and control the radio/CD system directly from the steering wheel. 4. Consider using only the newly developed digital radio/CD systems offering the search, scan, features. 5. Consider having the passenger operate the radio/CD system if such alternative is available. It is ciearly evident that more research is needed to assess driver distraction associated with in-vehicle devices. More resources are needed to support training, research, and development in this area. This will undoubtedly result in better design guidelines, smarter drivers, as well as better and safer products. Finally, it is suggested that a nation-wide campaign on driver education and safety is needed to alleviate the risks associated with telematics and other distracting devices. REFERENCES Alm, H., & Nilsson, L. (1994). Changes in driver behavior as a function of hands free mobile phones - A simulator study. Accident Analysis & Prevention, 26, 44 1-451. Alm, H., & Nilsson, L. (1995). The effects of a mobile telephone task on driver behavior in a car following situation. Accident Analysis & Prevention, 27, 707-7 15. American Psychological Association. (1992). Ethical principles of psychologist and code of conduct. American Psychologist, 47, 1597-1611. Brown, I. D., Tickner, A. H., & Simmonds, D. C. V. (1 969). Interference between concurrent tasks of driving and telephoning. Journal of Applied Psychology, 53,4 19-424. Hancock, P. A., & Scallen, S. F. (1999). The driving question. TransportationHuman Factors, 1,47-55. McKnight, J. & McKnight, S. (1991, January). The effect of cellular phone use upon driver attention. Washington, DC: National Public Service Research Institute. (Funded by AAA Foundation for Traffic Safety). McKnight, J. & McKnight, S. (1993). The effect of cellular phone use upon driver attention. Accident Analysis & Prevention, 25, 259-265. Srinivasan, R., & Jovanis, P. P. (1 997). Effect of selected invehicle route guidance systems on driver reaction times. Human Factors, 39,200-215. Streeter, Vitello, & Wonsiewics (1 985). International Journal of Man-Machine Studies, 22,549-562. Violanti, J. M., & Marshall, J. R. (1996). Cellular phones and traffic accidents: An epidemiological approach. Accident Analysis and Prevention, 28,265-210. Zwahlen, H. T., Adams, C. C., & Schwartz, P. J. (1988). Safety aspects of cellular telephones in automobiles. Proceedings of the ISATA Conference, Florence, Italy.