اثر حواس پرتی و تجربه در آگاهی از وضعیت و رانندگی شبیه سازی شده

Abstract This study examined the impact of cell phone conversation on situation awareness and performance of novice and experienced drivers. Driving performance and situation awareness among novice drivers ages 14–16 (n = 25) and experienced drivers ages 21–52 (n = 26) were assessed using a driving simulator. Performance was measured by the number of driving infractions committed: speeding, collisions, pedestrians struck, stop signs missed, and centerline and road edge crossings. Situation awareness was assessed through a query method and through participants’ performance on a direction-following task. Cognitive distractions were induced through simulated hands-free cell phone conversations. The results indicated that novice drivers committed more driving infractions and were less situationally aware than their experienced counterparts. However, the two groups suffered similar decrements in performance during the cell phone condition. This study provides evidence of the detrimental effects of cell phone use for both novice and experienced drivers. These findings have implications for supporting driving legislation that limits the use of cell phones (including hands-free) in motor vehicles, regardless of the driver’s experience level.

. Introduction Many studies have shown that talking on a cell phone while driving significantly influences driver performance. Furthermore, consumers are purchasing cell phones at increasing rates. As the number of cell phone users increases, the potential health risks also increase not only for those who choose to converse while driving, but also for passengers, pedestrians, and other drivers (Ferguson, 2003, Lam, 2002 and Peters and Peters, 2002). In an analysis of nearly 700 cell phone-related accidents, Redelmeier and Tibshirani (1997) concluded that talking on a cell phone increased the probability of a collision between 3 and 6.5 times. They also suggested that these distraction effects are comparable to a blood–alcohol-content above the legal limit. In fact, Strayer, Drews, and Crouch (2006) found that in a driving simulation task, cell phone users showed greater impairments as measured by increased number of rear-end collisions and time required to regain speed following braking than drivers who were legally drunk (i.e., blood–alcohol-content of 0.08). Additionally, Strayer and Johnston (2001) reported that drivers engaged in cell phone conversations missed twice as many traffic signals and had slower reaction times. Consiglio, Driscoll, Witte, and Berg (2003) also found that cell phone use (hand-held or hands-free) slowed drivers’ braking reactions compared to when they drove without distraction or when listening to music on the radio. 1.1. Role of situation awareness in driving Research on situation awareness (SA) is often traced back to military aviation studies, but SA is crucial to the performance of any dynamic complex task, including driving in heavy traffic (Endsley, 1995). SA involves identifying relevant environmental stimuli or cues, integrating that information into the operator’s knowledge base to form a mental model or representation of the situation, and using that representation to project the occurrence of events in the near future (see Dominguez, 1994, Endsley, 1990 and Kass et al., 1991). As drivers move through the environment, they must identify the relevant information in rapidly changing traffic patterns (e.g., distance to other vehicles, closing speed) and be prepared to react to events that may occur (e.g., car backing out of driveway, stop sign) to avoid accidents. To achieve SA, individuals must rely on perception and pattern recognition abilities (Durso and Gronlund, 1999 and Kass et al., 1991), attention and working memory (Gugerty, 1997 and Wickens and Hollands, 2000), as well as long-term memory (e.g., Endsley, 1995). Therefore, cognitive distractions that tax a driver’s attention or memory load may adversely impact SA. Recently, researchers (e.g., Beede and Kass, 2006, Garcia-Larrea et al., 2001, McKnight and McKnight, 1993 and Recarte and Nunes, 2003) have provided empirical evidence that driving performance suffers as a result of such cognitive distractions as cell phone use. These distractions may become particularly important safety issues when motorists are navigating through changing traffic patterns while attempting to maintain SA. Attention and hazard detection, aspects of SA, are known to be adversely affected by the cognitive distractions of cell phone conversation (Strayer & Johnston, 2001). 1.2. Experience level and situation awareness Research on risk exposure of younger drivers indicates that they are more likely to speed, pull into smaller gaps in traffic, and glance away from the road for longer intervals than experienced drivers (see Ferguson, 2003, Strayer and Drews, 2004 and Underwood et al., 2002). Crundall and Underwood (1998) investigated the differences in spatial strategy between novice and experienced drivers under different road conditions by examining participants’ visual attention. Experienced drivers employed a more flexible form of spatial strategy, such as searching for alternative routes, while novice drivers had rigid spatial strategies and usually focused on the one possible strategy that their visual search allowed. Lacking experience, novice drivers may not have learned to cope with the cognitive load imposed by complex road conditions while simultaneously attending to the overall demands of the driving task. This may result in a loss of SA and an inability to avoid collisions resulting in injury or death. The current experiment was designed to test the hypothesis that cell phone conversations disrupt SA and impair driving performance by preventing drivers from attending to situation-relevant stimuli such as speed limit postings, stop signs, pedestrians, and other traffic. These failings should manifest themselves in terms of increased driving infractions and an inability to take on an additional task (direction following). Prior research suggests that practice effects (e.g., Ferguson, 2003 and Strayer and Drews, 2004), mental models (e.g., Langham, Hole, & Edwards, 2002), and flexible spatial strategies (e.g., Crundall & Underwood, 1998) developed through experience enhance operators’ performance. Thus, experience level was expected to mitigate some of the decrements in driving performance and SA associated with cell phone conversations.

4. Results 4.1. Driving infractions To control for experiment-wide error rate associated with conducting multiple analyses of variance (ANOVA) on the 6 different driving infraction variables, a multivariate ANOVA (MANOVA) was performed. The dependent variables analyzed included the number of collisions, pedestrians hit, speeding violations, stop signs missed, centerline crossings, and road-edge excursions. Fig. 1 presents the means for the total number of infractions made by novices and experienced drivers across conditions. The MANOVA indicated significant main effects of experience level (F(6, 42) = 16.20, p < 0.001, partial ω2 = 0.48) and cell phone use (F(6, 42) = 9.60, p < 0.001, partial ω2 = 0.34). No significant interaction was found (F(6, 42) = 1.54, p = 0.19, partial ω2 = 0.03), suggesting that when drivers use a cell phone they suffer the same amount of performance decrement regardless of experience level. Driving infractions. Fig. 1. Driving infractions. Figure options Because MANOVA main effects of experience level and cell phone use were found, the univariate analyses of the six dependent variables were examined. These analyses revealed that novice drivers were involved in significantly more collisions with other vehicles (Mnov = 2.12, SD = 0.97 vs. Mexp = 1.12, SD = 0.95; F(1, 47) = 15.28, p < 0.001, partial ω2 = 0.12), drove through significantly more stop signs (Mnov = 1.52, SD = 0.87 vs. Mexp = 0.27, SD = 0.45; F(1, 47) = 42.60, p < 0.001, partial ω2 = 0.29), and crossed the centerline significantly more often (Mnov = 1.64, SD = 1.75 vs. Mexp = 0.62, SD = 0.85; F(1, 47) = 6.66, p < 0.05, partial ω2 = 0.05). No significant effects of experience were found for the number of pedestrians struck (Mnov = 1.08, SD = 1.00 vs. Mexp = 0.69, SD = 0.84; F(1, 47) = 2.07, p > 0.05, partial ω2 = 0.01), speeding violations (Mnov = 4.60, SD = 2.27 vs. Mexp = 3.81, SD = 1.88; F(1, 47) = 1.68, p > 0.05, partial ω2 = 0.01), or road-edge excursions (Mnov = 0.56, SD = 0.82 vs. Mexp = 0.31, SD = 0.62; F(1, 47) = 1.41, p > 0.05, partial ω2 = 0.00). Not surprisingly, these results suggest that experienced drivers had a clear performance advantage in the driving simulator environment even when they reported less experience with video games. The impact of the cell phone conversation on driving performance was elucidated by the following univariate results. Drivers in the cell phone condition were involved in significantly more collisions with other vehicles (Mcell = 2.04, SD = 0.89 vs. Mctrl = 1.19, SD = 1.10; F(1, 47) = 10.39, p < 0.01, partial ω2 = 0.09), struck more pedestrians (Mcell = 1.28, SD = 0.98 vs. Mctrl = 0.50, SD = 0.70; F(1, 47) = 10.14, p < 0.01, partial ω2 = 0.08), exceeded the posted speed limits more frequently (Mcell = 5.24, S.D = 1.94 vs. Mctrl = 3.19, SD = 1.74; F(1, 47) = 15.16, p < 0.001, partial ω2 = 0.12), and drove through more stop signs (Mcell = 1.12, SD = 1.01 vs. Mctrl = 0.65, SD = 0.80; F(1, 47) = 4.43, p < 0.05, partial ω2 = 0.03). Cell phone use did not significantly impact the number of times drivers crossed the centerline (Mcell = 1.36, SD = 1.75 vs. Mctrl = 0.88, SD = 1.07; F(1, 47) = 1.16, p > 0.05, partial ω2 = 0.00), or the number of times they drove off the road (Mcell = 0.52, SD = 0.65 vs. Mctrl = 0.35, SD = 0.80; F(1, 47) = 0.59, p > 0.05, partial ω2 = 0.00). 4.2. SA questions Fig. 2 presents the total number of SA questions answered correctly as a function of driver experience and distraction condition. The experienced group of drivers (M = 7.54, SD = 1.42) correctly answered significantly more questions than did the novice drivers (M = 4.76, SD = 2.18; F(1, 47) = 44.90, p < 0.001, partial ω2 = 0.46). The effect of the cell phone conversation was evident in that drivers who were engaged in conversation (M = 4.88, SD = 1.83) answered significantly fewer questions correctly than did those in the control condition (M = 7.42, SD = 2.00; F(1, 47) = 36.80, p < 0.001, partial ω2 = 0.41). The experience level by distracter interaction was not significant (F(1, 47) = 0.00, p > 0.05, partial ω2 = 0.00). SA questions. Fig. 2. SA questions. Figure options 4.3. Turns missed The ability to follow a set of driving directions was also used as an indicator of situation awareness (see Fig. 3). Novices were less able to follow directions and missed an average of 2.40 turns (SD = 1.73) whereas experienced drivers missed an average of just over one turn during the driving scenario (M = 1.11, SD = 1.11; F(1, 47) = 16.32, p < 0.001, partial ω2 = 0.23). The distraction of the cell phone also reduced drivers’ ability to follow directions (F(1, 47) = 43.57, p < 0.001, partial ω2 = 0.45). Drivers not distracted by the cell phone missed, on average, less than one turn (M = 0.77, SD = 0.95) whereas drivers engaged in conversation missed 2.76 turns (SD = 1.45). Further, the ANOVA indicated a small, but significant interaction of experience and distracter conditions (F(1, 47) = 4.19, p < 0.05, partial ω2 = 0.06). Novices missed an average of 1.08 turns (SD = 1.16) in the control condition and an average of 3.62 turns (SD = 1.19) in the cell phone condition. Alternatively, experienced drivers had little difficulty in the control condition, missing an average of only 0.50 turns (SD = 0.65), but again, those in the cell phone condition made more than three times as many errors (M = 1.83, SD = 1.11). A Tukey HSD revealed that experienced drivers in the cell phone condition missed significantly more turns than when they were not talking on a cell phone. Thus, while the effect of the cell phone was slightly greater for novice drivers, experience did not fully mitigate the detrimental effects of cell phone use on SA in terms of the ability to follow a printed set of driving directions. Missed turns. Fig. 3. Missed turns.