How (where) Does Music Background Hamper Driver Behaviour?

OBJECTIVE: The current study examined the effects of music on Hazard Perception - a skill that serves as a proxy for safe driving. BACKGROUND: There is contradictory evidence whether or not music engagement leads to decremented driver performance and compromises traffic safety. METHOD: In the study, 36 participants performed a standard Video-Based Hazard Perception Test under three aural conditions: Road and Traffic Sounds (RS); RS + Driver-Preferred Music; RS + Alternative Music. RESULTS: The results show no effect of aural backgrounds (including music) on the situation awareness portion of the driving task. CONCLUSION: Music background might affect later stages of the driving task such as response selection and/or response execution (mitigation). APPLICATION: The investigation of human factors related to vehicular control should include how (where) music might trigger failures in perception and/or behaviour.

Driver distraction and its effects on partially automated driving performance: A driving simulator study among young-experienced drivers.

Drivers of partially automated vehicles (PAVs) are relieved from parts of the driving tasks allocated to the automated driver. Ironically, these drivers are obligated to continuously monitor the driving task at all times and keep their attention on the roadway. This reduction in the driving task's demands and cognitive workload may encourage drivers to engage with non-driving related tasks (NDRT), which may impair drivers' awareness of the road environment and, as a result, compromise safety. This study examined how engagement with a visual-manual NDRT affects the driving performance of PAV drivers. Thirty-seven participants were randomly assigned to one of two experimental conditions in a driving simulator. Each consisted of two simulated drives. The first experimental condition included one drive under manual driving conditions and another under partially automated driving conditions (i.e., L2). Both drives had no NDRT involved. The second experimental condition included one drive under L2 without an NDRT and one drive under L2, including engagement with an NDRT. Participants' eye movements and heart rate were recorded throughout the experiment. Across various measures, the findings showed that under L2 driving conditions, engagement with an NDRT impairs driving performance in two primary aspects: (1) drivers were less aware of road hazards, and (2) their mental workload was higher when they engaged with an NDRT. In addition, the findings reveal that for drivers engaged with an NDRT, the attentional time-sharing strategy between the NDRT and the roadway monitoring task affected the probability of identifying a hazard. This study shows the adverse effects of engagement with an NDRT under L2 driving conditions on driving performance. Future studies should examine different interventions to mitigate these effects, assuring that drivers are constantly aware of the roadway environment.

Does gender affect the driving performance of young patients with diabetes?

Recent evidence suggests that poor glycemic control among young patients with type 1 diabetes mellitus (T1DM) has negative cognitive and physical effects, whose extent is gender-dependent. For example, female patients with diabetes present more physical and cognitive limitations than male patients in terms of cognitive adjustment, quality of decision making, and functioning. Studies about traffic safety report that diabetic drivers are at increased risk of being involved in road crashes, especially when driving in a state of hypoglycemia under which their blood glucose level is too low. We have recently demonstrated that acute hyperglycemia (when the blood glucose level is too high) can also lead to poor driving performance among T1DM young adult patients. Against this background, the objective of the present study was to find out whether gender affects the driving performance of young drivers with diabetes. Twenty-six T1DM drivers participated in a counterbalanced crossover experiment. While being monitored by an eye tracker, they drove a driving simulator and twice navigated through the nine hazardous scenarios: once under a normal blood glucose (euglycemia) level and once high blood glucose (hyperglycemia) level. The first main result is that young female drivers are more affected by diabetes than young male drivers, regardless of momentary glycemic changes. The second main result is that poor glycemic control substantially deteriorates hazard perception and driving performance of young males with diabetes. Thus, it is argued that an uncontrolled state of a high blood glucose level may be more hazardous for young males with diabetes since it negatively impacts their driving performance.

The Effects of an In-vehicle Collision Warning System on Older Drivers' On-road Head Movements at Intersections.

With age might come a decline in crucial driving skills. The effect of a collision warning system (CWS) on older drivers' head movements behavior at intersections was examined. Methods: Twenty-six old-adults, between 55 and 64 years of age, and 16 Older drivers between 65 and 83 years of age, participated in the study. A CWS (Mobileye Inc.) and a front-back in-vehicle camera (IVC) were installed in each of the participants' own vehicles for 6 months. The CWS was utilized to identify unsafe events during naturalistic driving situations, and the IVC was used to capture head direction at intersections. The experimental design was conducted in three phases (baseline, intervention, and carryover), 2 months each. Unsafe events were recorded by the CWS during all phases of the study. In the second phase, the CWS feedback was activated to examine its effect on drivers' head movement' behavior at intersections. Results: Older drivers (65+) drove significantly more hours in total during the intervention phase (M = 79.1 h, SE = 10) than the baseline phase (M = 39.1 h, SE = 5.3) and the carryover phase (M = 37.7 h, SE = 5.4). The study revealed no significant differences between the head movements of older and old-adult drivers at intersections. For intersection on the left direction, a significant improvement in drivers' head movements' behavior was found at T-junctions, turns and four-way intersections from phase 1 to phase 3 (p < 0.01), however, two intersection types presented a decrease along the study phases. The head movements' behavior at roundabouts and merges was better at phase 1 compared to phase 3 (p < 0.01). There was no significant reduction of the mean number of CWS unsafe events across the study phases. Conclusions: The immediate feedback provided by the CWS was effective in terms of participants' head movements at certain intersections but was harmful in others. However, older drivers drove many more hours during the active feedback phase, implying that they trusted the system. Therefore, in the light of this complex picture, using the technological feedback with older drivers should be followed with an additional mediation or follow-up to ensure safety.

Acute hyperglycaemia can impair driving skill in young type 1 diabetes mellitus patients.

AIM: Drivers with diabetes are at increased risk of being involved in road accidents. Therefore, this study aimed to evaluate the effects of acute hyperglycaemia (AH) compared with euglycaemia on driving ability in patients with type 1 diabetes mellitus (T1DM). METHODS: Eighteen drivers with T1DM were asked to navigate twice through nine hazardous scenarios, using a driving simulator, during euglycaemia and then again during AH (mean blood glucose: 138 ± 34 mg/dL and 321 ± 29 mg/dL, respectively) in a counterbalanced crossover study. Driving performance was continually monitored for driving speed, steering wheel angle, acceleration, and location and velocity of other vehicles and obstacles, with drivers wearing a mobile head-mounted eye-tracking system. RESULTS: The main findings were that, during AH, participants were less likely to identify a hazard [probability of identification (POI): 0.5725 ± 0.5], glanced fewer times at the hazard (3.24 ± 5.9), maintained shorter headway (between-vehicle) distance (mean: 40.87 ± 20.15 m) and had an increased number of braking events per km driven (6.69 ± 5.20) compared with driving during euglycaemia (POI: 0.733 ± 0.4; number of glances: 3.69 ± 6.99; headway distance: 50.46 ± 26.2 m; number of braking events per km driven: 4.31 ± 3.87; P < 0.05 for all parameters). CONCLUSION: This study provides evidence that AH impairs driving performance in young T1DM patients by demonstrating the negative effects of AH on both hazard perception and speed management.

Improving Drivers' Hazard Perception and Performance Using a Less Visually-Demanding Interface.

In-vehicle devices and infotainment systems occasionally lead to driver distraction, and as a result, increase the risk of missing on-road information. In the current study, a novel multi-touch interface for an in-vehicle infotainment system was evaluated, which potentially requires less visual attention and thus may reduce distraction and increase safety. The interface was compared with a functionally similar control interface in terms of hazard perception metrics and mental workload. Twenty-two participants drove a simulated route once with each system. During each drive, which included eight potentially-hazardous scenarios, participants were instructed to interact with one of the in-vehicle interfaces to perform phone calls or to navigate to specified destinations. Eye-gaze data were collected throughout the drive to evaluate whether participants detected the hazards while interacting with the in-vehicle interface, how much time they needed to identify them, and for how long they engaged with the secondary task. Additionally, after each drive, participants completed a NASA R-TLX questionnaire to evaluate their subjective workload during their engagement with the secondary tasks. Participants using the multi-touch interface needed less time to complete each secondary task and were quicker at identifying potential hazards around them. However, the probability of detecting hazards was similar for both interfaces. Finally, when using the multi-touch interface, participants reported lower subjective workload. The use of a multi-touch interface was found to improve drivers' performance in terms of identifying hazards quicker than the control condition. The road safety and driver distraction implications of this novel interface are discussed.

Traumatic brain injury hinders learning of road hazard awareness by repeated exposure to video-based hazards.

OBJECTIVE: To better understand hazard awareness abilities among traumatic brain injury (TBI) survivors of which little is currently known. TBI survivors express degradation in driving abilities, particularly the proactive strategy in which indicators of potentially hazardous situations are sought and identified. The current study examined differences in hazard awareness learning between TBI survivors and noninjured control individuals matched for age and driving experience. METHOD: Forty individuals equally divided among the 2 groups were assessed by exposure to repetitive video-based hazard scenarios, which have been shown to improve hazard awareness in noninjured individuals. Differences in participants' eye movements and behavioral response while watching video clips of genuine traffic scenes were recorded. RESULTS: Although survivors of TBI demonstrated relatively intact hazard awareness abilities under baseline conditions, they failed to learn from repetitive presentation of the same hazardous situation (i.e., they did not improve hazard detection) and thus failed to adjust their scanning and behavioral reaction (e.g., time to reaction, adapt of scanning behavior). Differences were more prominent for hidden hazards. Our results show impoverished anticipation abilities in driving simulation tasks performed in the subacute recovery phase after TBI and that differences in materialized hazards awareness are distinguishable between TBI survivors and noninjured drivers of similar age and driving experience. CONCLUSIONS: Our findings signal the need for further research to clarify the relationship between TBI and hazard awareness training that might be supportive of driving rehabilitation after TBI. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

What can a hazard function teach us about drivers' perception of hazards?

OBJECTIVE: Hazard perception (HP) is typically defined as the ability to read the road and anticipate hazardous situations. Several studies have shown that HP is a driving skill that correlates with traffic crashes. Measuring HP differences between various groups of drivers typically involves a paradigm in which participants observe short videos of real-world traffic scenes taken from a driver's or a pedestrian's perspective and press a response button each time they identify a hazard. Young, inexperienced drivers are considered to have poor HP skills compared to experienced drivers, as evident by their slower response times (RTs) to road hazards. Nevertheless, though several studies report RT differences between young, inexperienced and experienced drivers, other studies did not find such differences. We have already suggested that these contradictory findings may be attributed to how cases of no response-that is, a situation where a participant did not respond to a hazard-are being treated. Specifically, we showed that though survival analysis handles cases of no response appropriately, common practices fail to do so. These methods often replace a case of no response with the mean RT of those who responded or any other central tendency parameters. The present work aims to show that treating cases of no response appropriately as well as selecting a distribution that fits the RT data is more than just a technical phase in the analysis. METHOD: This work used simulation of predefined distributions and real-world data. RESULTS: It was demonstrated that selecting the appropriate distribution and treating nonresponse cases appropriately affect the shape and characteristics of the density, survival, and hazard functions. CONCLUSIONS: The suggested process has the ability to provide researchers with additional information regarding the nature of the traffic scenes that enables differentiating between various hazardous situations and between various users with different characteristics such as age or experience.

The effects of repetitive presentation of specific hazards on eye movements in hazard perception training, of experienced and young-inexperienced drivers.

Recent evidence shows that compared to experienced drivers, young-inexperienced drivers are more likely to be involved in a crash mainly due to their poor hazard perception (HP) abilities. This skill develops with experience and may be developed through training. We assumed that as any other skill, HP developed through implicit learning. Nevertheless, current training methods, rely on deliberate learning where young-inexperienced drivers are instructed what hazards that they should seek and where they might be located. In this exploratory study, we investigated the effectiveness of a novel training procedure, in which learners were repeatedly exposed to target video clips of driving scenarios embedded within filler scenarios. Each of the target videos included scenarios of either a visible hazard, a hidden materialized hazard or hidden unmaterialized hazard. Twenty-three young-inexperienced drivers and 35 experienced drivers participated in training session followed by a learning transference testing session and 24 additional young-inexperienced drivers participated only in the transference testing session with no training, during which participants were shown novel hazards video clips. Participants responded by pressing a button when they identified a hazard. Eye movement was also tracked using fixations patterns as a proxy to evaluate HP performance. During training, young-inexperienced drivers gradually increased their focus on visible materialized hazards but exhibited no learning curve with respect to hidden hazards. During the learning transference session, both trained groups focused on hazards earlier compared to untrained drivers. These results imply that repetitive training may facilitate HP acquisition among young-inexperienced drivers. Patterns concerning experienced drivers are also discussed.

The effects of brief visual interruption tasks on drivers' ability to resume their visual search for a pre-cued hazard.

Driver visual distraction is known to increase the likelihood of being involved in a crash, especially for long glances inside the vehicle. The detrimental impact of these in-vehicle glances may carry over and disrupt the ongoing processing of information after the driver glances back up on the road. This study explored the effect of different types of visual tasks inside the vehicle on the top-down processes that guide the detection and monitoring of road hazards after the driver glances back towards the road. Using a driving simulator, 56 participants were monitored with an eye tracking system while they navigated various hazardous scenarios in one of four experimental conditions. In all conditions, a potential hazard was visible 4-5s before the driver could strike the potential hazard were it to materialize. All interruptions were exactly two seconds in length. After the interruption the potential hazard again became visible for about a half-second after which the driver passed by the hazard. The nature of the in-vehicle visual interruption presented to the participants was varied across conditions: (1) Visual interruptions comprised of spatial, driving unrelated, tasks; (2) visual interruptions comprised of non-spatial, driving unrelated, tasks; (3) visual interruptions with no tasks added; and (4) no visual interruptions. In the first three conditions drivers glancing on the forward roadway was momentarily interrupted (either with or without a task) just after the potential hazard first became visible by the occurrence of an in-vehicle task lasting two seconds. In the last condition (no interruptions) the driver could not see the potential hazard after it just became visible because of obstructions in the built or natural environment. The obstruction (like the interruption) lasted for two seconds. In other words, across all conditions the hazard was visible, then became invisible, and finally became visible again. Importantly, the results show that the presence of an interruption (as opposed to an obstruction) negatively impacted drivers' ability to anticipate the potential hazard. Moreover, the various types of interruptions had differential effects on hazard detection. The implications of this study for the design of in-vehicle displays are discussed.

Driving speed of young novice and experienced drivers in simulated hazard anticipation scenes.

OBJECTIVE: In this study, we aimed to demonstrate analysis methods that are sensitive to speed-related differences between experienced and young novice drivers. These differences may be linked to determining which group is better at anticipating hazards. BACKGROUND: Awareness of hazardous situations, especially potential ones, is a major discriminator between experienced and young novice drivers who tend to misidentify potential hazards in the traffic environment. METHOD: Experienced and young novice drivers were asked to drive a sequence of 14 scenarios in a driving simulator. Scenarios were created in two city areas, residential and business district, and included various types of hazards. Group homogeneity of speed for each group of drivers was computed for each scenario, and two business district scenarios were subjected to piecewise linear regression analysis. RESULTS: Group homogeneity analysis showed consistent and significant experience-based differences across all scenarios, revealing that the experienced drivers as a group were more homogenous in choosing their driving speed. Differences between groups were larger in the business district where speed was less restricted. Piecewise linear regression analysis revealed that experienced drivers approached uncontrolled intersections by slowing down and responded earlier to materialized events. CONCLUSION: Young novice drivers were more likely than experienced drivers to choose diverse values of speed at any given road section, presumably due to their poor awareness of potential and hidden hazards. Unlike other analysis methods, it is argued that group homogeneity of speed is a more sensitive measurement to reveal these gaps. APPLICATION: Speed management could be the basis of future hazard anticipation simulator assessments.

Effects of cues on target search behavior.

Cues in visual scanning task can improve decision accuracy, and they may also affect task performance strategies. We tested the effects of cues on the performance of binary classifications, on the screen scanning procedure participants employed, and on the reported effort in a simulated quality control task. Participants had to decide whether each item in a 5 × 5 matrix of items was intact or faulty. In half the experimental blocks decisions could only be based on the visual properties of the items. In the other half, participants also saw imperfect binary cues and could use them to classify the items as faulty or intact. We used eye tracking to study scan patterns and fixation durations on items. Decision performance improved with cues, and cues affected the scanning of items, with participants mainly scanning cued items and tending to scan them longer. Participants stated that cues reduced their effort when cues were highly valid. We conclude that strategic choices to focus on suspected areas determined the screen scanning procedure, the amount of effort invested in single decisions, and the accuracy of the decisions. We therefore suggest using likelihood ratio cues to help optimize the scanning procedure.

The effects of momentary visual disruption on hazard anticipation and awareness in driving.

OBJECTIVE: Driver distraction is known to increase crash risk, especially when a driver glances inside the vehicle for especially long periods of time. Though it is clear that such glances increase the risk for the driver when looking inside the vehicle, it is less clear how these glances disrupt the ongoing processing of information outside the vehicle once the driver's eyes return to the road. The present study was aimed at exploring the effect of in-vehicle glances on the top-down processes that guide the detection and monitoring of hazards on the forward roadway. METHOD: Using a driving simulator, 12 participants were monitored with an eye-tracking system while they navigated various hazardous scenarios. Six participants were momentarily interrupted by a visual secondary task (simulating a glance inside the vehicle) prior to the occurrence of a potential hazard and 6 were not. RESULTS: Eye movement analyses showed that interrupted drivers often failed to continue scanning for a potential hazard when their forward view reappeared, especially when the potential threat could not easily be localized. Additionally, drivers' self-appraisal of workload and performance of the driving task indicated that, contrary to what one might expect, drivers in the interruption condition reported workload levels lower than and performance equal to drivers in the no interruption condition. CONCLUSIONS: Drivers who are momentarily disrupted even for a brief duration are at risk of missing important information when they return their gaze to the forward roadway. In addition, because they are not aware of missing this information they are likely to continue engaging in in-vehicle tasks even though they are demonstrably unsafe. The implications for safety, calibration, and targeted remediation are discussed.

Formation and Evaluation of Act and Anticipate Hazard Perception Training (AAHPT) intervention for young novice drivers.

OBJECTIVE: Young novice drivers' poor hazard perception (HP) skills are a prominent cause for their overinvolvement in traffic crashes. HP, the ability to read the road and anticipate forthcoming events, is receptive to training. This study explored the formation and evaluation of a new HP training intervention-the Act and Anticipate Hazard Perception Training (AAHPT), which is based upon exposing young novice drivers to a vast array of actual traffic hazards, aiming to enhance their ability to anticipate potential hazards during testing. METHOD: Forty young novices underwent one of 3 AAHPT intervention modes (active, instructional, or hybrid) or a control group. Active members observed video-based traffic scenes and were asked to press a response button each time they detected a hazard. Instructional members underwent a tutorial that included both written material and video-based examples regarding HP. Hybrid members received a condensed theoretical component followed by a succinct active component. Control was presented with a road safety tutorial. Approximately one week later, participants performed a hazard perception test (HPT), during which they observed other movies and pressed a response button each time they detected a hazard. Twenty-one experienced drivers also performed the HPT and served as a gold standard for comparison. RESULTS: Overall, the active and hybrid modes were more aware of potential hazards relative to the control. CONCLUSIONS: Inclusion of an active-practical component generates an effective intervention. Using several evaluation measurements aids performance assessment process. Advantages of each of the training methodologies are discussed. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.

Exploring the effects of driving experience on hazard awareness and risk perception via real-time hazard identification, hazard classification, and rating tasks.

This study investigated the effects of driving experience on hazard awareness and risk perception skills. These topics have previously been investigated separately, yet a novel approach is suggested where hazard awareness and risk perception are examined concurrently. Young, newly qualified drivers, experienced drivers, and a group of commercial drivers, namely, taxi drivers performed three consecutive tasks: (1) observed 10 short movies of real-world driving situations and were asked to press a button each time they identified a hazardous situation; (2) observed one of three possible sub-sets of 8 movies (out of the 10 they have seen earlier) for the second time, and were asked to categorize them into an arbitrary number of clusters according to the similarity in their hazardous situation; and (3) observed the same sub-set for a third time and following each movie were asked to rate its level of hazardousness. The first task is considered a real-time identification task while the other two are performed using hindsight. During it participants' eye movements were recorded. Results showed that taxi drivers were more sensitive to hidden hazards than the other driver groups and that young-novices were the least sensitive. Young-novice drivers also relied heavily on materialized hazards in their categorization structure. In addition, it emerged that risk perception was derived from two major components: the likelihood of a crash and the severity of its outcome. Yet, the outcome was rarely considered under time pressure (i.e., in real-time hazard identification tasks). Using hindsight, when drivers were provided with the opportunity to rate the movies' hazardousness more freely (rating task) they considered both components. Otherwise, in the categorization task, they usually chose the severity of the crash outcome as their dominant criterion. Theoretical and practical implications are discussed.

The perception of pedestrians from the perspective of elderly experienced and experienced drivers.

We examined hazard perception (HP) abilities among elderly experienced and experienced drivers, with regard to the presence of pedestrians in residential areas. Two evaluation methods were used: (a) observation of traffic scene videos and pressing a button when a hazardous situation was identified, and (b) driving in a driving simulator. The results of the video observation method showed that elderly drivers had a longer response time for hazard detection. In addition, four of the eight pedestrian-related events were difficult for elderly drivers to perceive when compared to experienced drivers. Elderly drivers, shown to have limited useful field of view, may also be limited in their ability to detect hazards, particularly when located away from the center of the screen. Results from the simulator drive showed that elderly drivers drove about 20% slower than experienced drivers, possibly being aware of their deficiencies in detecting hazards and slower responses. Authorities should be aware of these limitations and increase elderly drivers' awareness to pedestrians by posting traffic signs or dedicated lane marks that inform them of potential upcoming hazards.

Drivers' perception of vulnerable road users: a hazard perception approach.

The present study examined how experienced and young-inexperienced drivers (either trained in hazard perception or not) respond to and identify pedestrians when they appear in residential roads within populated neighborhoods and in urban roads located outside neighborhoods and usually less populated. As part of a hazard perception test, participants were connected to an eye tracking system and were asked to observe 58 traffic scene movies and press a response button each time they detected a hazardous situation. Analyzing all pedestrian-related events revealed that, regardless of driving experience or training, drivers detect pedestrians less often when they appear in urban areas and more often when they appear in residential areas. Moreover, experienced drivers processed information more efficiently than young-inexperienced drivers (both trained and untrained) when pedestrians were identified. Visual search patterns in urban and residential traffic environments are discussed.

Age, skill, and hazard perception in driving.

This study examined the effects of age and driving experience on the ability to detect hazards while driving; namely, hazard perception. Studies have shown that young-inexperienced drivers are more likely than experienced drivers to suffer from hazard perception deficiencies. However, it remains to be determined if this skill deteriorates with advancing age. Twenty-one young-inexperienced, 19 experienced, and 16 elderly drivers viewed six hazard perception movies while connected to an eye tracking system and were requested to identify hazardous situations. Four movies embedded planned, highly hazardous, situations and the rest were used as control. Generally, experienced and older-experienced drivers were equally proficient at hazard detection and detected potentially hazardous events (e.g., approaching an intersection, pedestrians on curb) continuously whereas young-inexperienced drivers stopped reporting on hazards that followed planned, highly hazardous situations. Moreover, while approaching T intersections older and experienced drivers fixated more towards the merging road on the right while young-inexperienced drivers fixated straight ahead, paying less attention to potential vehicles on the merging road. The study suggests that driving experience improves drivers' awareness of potential hazards and guides drivers' eye movements to locations that might embed potential risks. Furthermore, advanced age hardly affects older drivers' ability to perceive hazards, and older drivers are at least partially aware of their age-related limitations.

The relation between driving experience and recognition of road signs relative to their locations.

OBJECTIVES: Examine how driving experience and expectations affect the ability of experienced drivers to identify traffic signs--specifically, no right turn (NRT) and no left turn (NLT) at intersections. BACKGROUND: Failure to heed signs is a frequent cause of accidents, and the authors focused on the contributions of experience and expectancy to sign identification. METHOD: Inexperienced and experienced drivers were connected to an eye tracker system and briefly exposed to various traffic scenes. Some of the pictures included an NRT sign at the expected location (on the right), and some included the same sign at an unexpected location (on the left). The same procedure was used with an NLT traffic sign. RESULTS: Experienced drivers identified traffic signs better than inexperienced drivers did when the signs were posted at the expected location but identified them worse than did inexperienced drivers when they were at unexpected locations. CONCLUSIONS: With experience, drivers' expectations regarding the expected location of traffic signs become so strong that violating these expectancies results in more identification errors among experienced drivers than among inexperienced drivers. To optimize experienced drivers' traffic sign identification, signs must be located in accordance with drivers' expectations--specifically, on the right side of the road. APPLICATIONS: When signs are misplaced, crashes can be caused by inappropriate placement rather than inappropriate driving. Highway designers should ensure that their design conforms to standards that shape experienced drivers' expectations.