Article

Vehicle Height Affects Drivers' Speed Perception Implications for Rollover Risk

Authors:
  • Human Factors North
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Abstract

The North American vehicle fleet has evolved in recent years to include an increasing percentage of pickups, sport utility vehicles (SUVs), and minivans. In 2002, sales of light trucks and vans accounted for almost half of all Canadian vehicle sales. The increased popularity of SUVs has been particularly striking, with a 143% increase in sales since 1993. Typically larger and heavier than automobiles, SUVs are built on frames that are more rigid and that ride higher, characteristics that not only provide increased physical protection to their occupants but also add to their overall appeal. SUVs, however, are involved in fatal rollover crashes at a much higher rate than cars. While this is undoubtedly due in part to their stiffer frames and higher centers of gravity, the manner in which SUVs are driven may also play a role. SUV drivers are often anecdotally reported to be overconfident, tending to overestimate their vehicle's capabilities. Evidence suggests that because they sit higher, drivers of SUVs (and vans and pickups) are less able to judge speed accurately. A study was conducted to assess drivers' chosen speed when they operated a simulated vehicle while viewing the road from a low eye height and a high eye height. Participants were instructed to drive, without reference to a speedometer, at a highway driving speed at which they felt comfortable and safe. As expected, drivers seated at a high eye height drove faster than when they were seated at a low eye height. The influence of driver eye height and lead vehicle size (large versus small) on the following distance from a slower-moving lead vehicle was also investigated. Regardless of eye height, the differences in following distances suggest that the size of the lead vehicle may affect how closely drivers choose to follow it.

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... However, drivers primarily estimate their speed by analyzing visual input through a process called optic flow. As one moves through the environment, the visual field in front expands and passes by (Rudin-Brown 2004). However, the low or high luminance and monotonous road environment make them a weak visual reference system. ...
... The studies that examine driver perception were carried out using different methodologies, by the experiments conducted in driving simulators (Ben-Bassat and Shinar 2011;Martens and Brouwer 2013;Pešić et al. 2019;Rudin-Brown 2004;Wu et al. 2017;Zheng et al. 2018), real traffic situations (Troscianko et al. 1999), tablet PCs and smart boards (Cicevic et al. 2017), by driver self-reports, i.e., questionnaire (Ojsteršek and Topolšek 2019), and also in virtual reality . The sample ranges from 14 to 200 respondents, while statistical analysis was most often used for data processing. ...
Article
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The major challenge of this paper is to examine how various forms of speed perception affect motor vehicle crash (MVC) involvement. To model this relationship, we use a type-2 fuzzy inference system (T2FIS). Another general challenge is to improve the performance of seven created T2FISs in a sense of compliance with the empirical data. This is achieved by a proposal of an algorithm based on the bee colony optimization (BCO) metaheuristic. The main novelty of this algorithm is the way how the testing points are selected in a type-2 fuzzy environment, which influences the execution efficiency. Data collection was carried out in twelve experiments. A total of 178 young drivers assessed the speed level from four positions; three of them relate to the speed perception of other vehicles on the road, while the remaining one represents the assessment of their own speed. At each position, three speed levels were assessed: 30, 50, and 70 km/h. As a result of the implemented methodology, a relationship between the various forms of speed perception and participation in MVCs can be quantified. The BCO-based algorithm achieved an average improvement of 21.17% in the performance of the initial T2FIS structures. The final results indicate that the drivers whose speed perception of the vehicle they are looking at from the rear side, as well as of the own vehicle, is poor have an elevated risk toward participation in MVCs compared to other forms of speed perception. This can be useful in various educational and recruitment procedures.
... However, drivers primarily estimate their speed by analyzing visual input through a process called optic flow. As one moves through the environment, the visual field in front expands and passes by (Rudin-Brown, 2004). However, the low or high luminance and monotonous road environment make them a weak visual reference system. ...
... The studies that examine driver perception were conducted using different methodologies, by the experiments conducted in driving simulators (Ben-Bassat & Shinar, 2011;Martens & Brouwer, 2013;Pešić et al., 2019;Rudin-Brown, 2004;Wu et al., 2017;Zheng et al. 2018), real traffic situations (Troscianko et al., 1999), tablet PCs and smart boards (Cicevic et al., 2017), by driver self-reports, i.e. questionnaire (Ojsteršek & Topolšek, 2019), and also in virtual reality . The sample ranges from 14 to 200 respondents, while statistical analysis was most often used for data processing. ...
Preprint
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This paper examines how a driver’s perception of various speed levels, as well as driver’s speed perception from different positions, affect the propensity for motor vehicle crashes (MVCs). Data collection is performed in twelve experiments. 178 young drivers assessed the speed level from four positions; three of them relate to the speed perception of other vehicles on the road, while the remaining one represents the assessment of own speed. At each position, three speed levels were assessed: 30, 50, and 70 km/h. To process data, seven Type-2 fuzzy inference systems (T2FISs) are designed and tested in a sense of compliance with the empirical data. As a result, a relationship between the various forms of speed perception and participation in MVCs can be quantified. To examine the initial conclusions, the optimization of each of these T2FISs is performed by implementing the bee colony optimization (BCO) metaheuristic. The BCO based algorithm proposed in this paper achieved an average improvement of 21.17% in the performance of the initial T2FIS structures. The final results indicate that the drivers whose speed perception of the vehicle they are looking at from the rear side, as well as of the own vehicle, is poor have an elevated risk toward participation in MVCs compared to other forms of speed perception. The best-found T2FIS structures can be used as a decision-making tool that quantifies the driver propensity for MVCs, which can be useful in various educational and recruitment procedures in the field of transportation and traffic safety.
... Green, 2009) as well as affecting driver response capacity to leading vehicle speed variations (Kang, 2008). Vehicle type such as four-wheel drives and SUVs (Sports Utility Vehicles), where the driver is seated at a considerable height above the road surface, was also likely to give the driver an inaccurate perception of the speed at which they are travelling, one study indicating two-thirds of SUV drivers were not aware that they were driving faster than when in a sports car, with some thinking they were driving slower ((Rudin-Brown, 2004) cited in (SWOV -Dutch Institute for Road Safety Research, 2007)). Drivers may also increase or underestimate speed after long, unbroken period of driving (SWOV -Dutch Institute for Road Safety Research, 2008) A recent study investigating drivers' speed choice when travelling through a roundabout in Baltic regions, found that the inscribed circle diameter of the roundabout was the single most influential factor for drivers when choosing speed, (Antov, Abel, Sürje, Rõuk, & Rõivas, 2009) Estimated speed of other vehicles can also influence drivers (Haglund & Åberg, 2000) as can the presence of a passenger though this appears to be more influential on young male drivers. ...
... Additionally, the more powerful the vehicle, the easier and quicker h speeds can be reached. Large wheels were also found to distort perceived speed (Rudin-Brown, 2004) Vehicle type also influences eventual impact speed through braking potential and providing the driver with adequate warning and time to react. Described briefly below are driver warning systems to assist the driver to react more quickly to an upcoming dangerous event. ...
... Larger vehicles are typically taller and provide the driver with a higher viewpoint and a better sight distance of the road ahead. However, Rudin-Brown (2004) found that headway to a lead vehicle increases when the lead vehicle is large, indicating driver compensation to the reduction in sight distance caused by the large vehicle. Individual safety gains relative to other drivers may be regarded as ''selfish safety,'' where a driver can obtain self-protection in a larger vehicle with a higher level of occupant safety in a multiple-car collision and a better line of sight of the road ahead. ...
... The ''bigger is safer'' attitude makes SUV drivers more likely to believe in any benefits relating to a larger vehicle, even if these benefits are illusory. For example, SUV drivers are more likely to accept a safety advantage from the increased visibility of a taller vehicle, even though a taller vehicle is likely to block the view of other drivers (Rudin-Brown, 2004), have greater blind spots, have a higher center of gravity, and be more prone to rollover and loss of control accidents (Kweon and Kockelman, 2003;Wenzel and Ross, 2005). The acceptance of illusory benefits is not due to an impaired knowledge of vehicle size and safety, as car drivers have a similar knowledge when tested. ...
Article
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A sample of 496 car and sport utility vehicle (SUV) drivers responded to questionnaires that examined attitudes toward vehicle size and safety. The aim of this research is to determine whether drivers perceive larger vehicles to be safer and whether this concern for safety motivates drivers to purchase SUVs. Alternatively, non–safety influences are also examined, including environmental concern, vehicle power, prestige, and vehicle utility. Perceptions that large vehicle are safer, off-road use, and prestige all relate strongly to SUV use. The safety arguments raised by SUV drivers appear to be based on an egocentric concern for “bigger is safer” rather than a broader understanding of vehicle fleet safety. To encourage sustainable transport, it is suggested that road safety policy should shift drivers' concerns from personal collision protection to overall road user protection.
... This issue has received much attention by researchers and highway and vehicle agencies [3][4][5][6][7]. There have since been continuing efforts by researchers to reduce fatalities and serious injuries of rollovers [8][9][10][11]. ...
Article
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Truck rollover crashes on horizontal curves have been recognized as one of the most serious types of crashes. Driver’s instantaneous emergency steering maneuvers (DIESM) play an important role in truck rollover crashes, but have not received much attention. In the present study, the radius of curvature of the actual vehicle travel path (AVTP) under DIESM was calculated based on the transient bicycle model. Rollover margins were used to evaluate the truck-rollover potential under DIESM. To calculate rollover margins, the lateral acceleration under DIESM was calculated based on the radius of the curvature of the AVTP. A rollover threshold formula was introduced to calculate vehicle’s rollover thresholds by distinguishing two turning conditions. According to rollover margins, the maximum safe instantaneous input of the steering wheel against rollover for trucks was obtained. Moreover, theoretical results were verified by computer simulation. Results showed: (1) The maximum safe instantaneous inputs of the steering wheel were 259°, 212°, 182°, 162°and 147°, respectively, at speeds of 60 km/h, 70 km/h, 80 km, 90 km and 100 km when the superelevation rate was 0, and (2) superelevation significantly affected truck-rollover potential; the worst turning condition was turning from the inside to the outside of the curve. Due to the consideration of the wheelbase, the centroid position, the tire’s cornering stiffness and the suspension roll gain, the prediction results were more accurate.
... Daha önce yapılan çalışmalar incelendiğinde, her ne kadar alanyazında özel olarak araç segmenti çalışması olmasa da, otomobilin gücü ve saldırgan sürüş arasında anlamlı ilişkiler elde eden çalışmalar mevcuttur (Bochner, 1971;Diekmann ve ark., 1996;Doob ve Gross, 1968;Haje ve Symbaluk, 2014;Krahé ve Fenske, 2002;McGarva ve Steiner, 2000). Örneğin Krahé ve Fenske (2002) tarafından yürütülen bir çalışmada, aracın motor gücündeki artışın, sürücünün daha hızlı araç sürmesine sebep olduğu, benzer şekilde Rudin-Brown (2004) tarafından gerçekleştirilen ve hız göstergesi olmayan bir sürüş simülatöründe insan davranışlarını inceleyen bir çalışmada, katılımcıların SUV yüksekliğindeyken normal yükseklikte yaptıklarından ortalama 7 km/s daha fazla hız yaptıkları görülmüştür. Bu çalışmaların aksine mevcut çalışmada yürütülen analizlerde hatalar, dalgınlıklar ve ihmaller, saldırgan ve sıradan ihlaller özelinde ve ek olarak pozitif sürücü davranışları özelinde segmente bağlı anlamlı grup farklılaşması bulunamadığı gibi farklı segment araca sahip sürücü grupları ve sürücü becerilerinin alt boyutlarından olan güvenlik becerileri etkileşimlerinin etkisinin de anlamlı olmadığı bulunmuştur. ...
Article
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Karayolu güvenliği, yol kullanıcıları, araçlar ve çevre ile ilgili birçok faktöre ve bu faktörlerin birbirleri ile olan ilişkilerine bağlıdır. En çok göz önünde olan yol kullanıcılarının sürücüler olması sebebiyle, trafik güvenliği araştırmalarında genel olarak sürücü davranışları odak noktası olarak alınmaktadır. Trafik ortamında kişilerden ve kişilik özelliklerinden ayrı olarak, sürücü davranışlarını şekillendiren birçok etmen mevcuttur. Örneğin, bir aracın kapasitesi sürücülerin trafikte ihlal ve/veya hata yapma, sürüş sırasında saldırgan davranma vb. tercihlerini etkileyen faktörlerden bir tanesi olarak görülebilir. Bu bağlamda, bu araştırmanın temel amacı, kullanılan araç segmenti ile sürücü davranışları ve sürücü becerileri arasındaki olası ilişkilerin incelenmesidir. Mevcut çalışma 20-62 yaş arası 183 sürücü ile gerçekleştirilmiştir. Veriler katılımcılardan demografik form, Sürücü Davranışları Anketi (SDA) ve Sürücü Becerileri Ölçeği (SBÖ) içeren internet tabanlı bir anket bataryası aracılığıyla toplanmıştır. Değişkenler arasındaki olası ilişkilerin test edilmesi amacıyla İki Değişkenli Korelasyon Analizi, Tek Yönlü Bağımsız Gruplar Kovaryans Analizleri (ANCOVA) ve Tek Yönlü Varyans Analizleri (ANOVA) sırasıyla uygulanmıştır. Yapılan analizler sonucunda kullanılan araç segmenti, sıradan ihlaller ve algısal-motor beceri değişkenleri ile pozitif ilişkili olarak bulunurken ileri analizlerde özellikle B, C ve D segmenti araç kullanıcılarının algısal-motor beceri değerlendirmelerinin birbirlerinden anlamlı derecede farklı olduğu bulunmuştur. Sürücü becerileri ve araç segmenti arasında test edilen bu ilişkinin, daha ayrıntılı analizlerle yapılacak gelecek çalışmalarda yararlı olacağı düşünülmektedir.
... In another study, Van They found only small effects in terms of speed underestimation for higher camera positions. 159 Similar results are observable when drivers have to judge their own speed while driving in 160 larger vehicles: ego-speed is underestimated when seated in a van or truck, as compared to a 161 sedan (Panerai, et al., 2001;Rudin-Brown, 2004). However, these results might also be 162 attributable to an increased feeling of safety when driving with a large vehicle and give no 163 direct information about the perception of distance. ...
Poster
Vehicle manufacturers are increasingly considering the implementation of camera-monitor systems (CMS) as replacement for conventional side-mounted rear-view mirrors on passenger vehicles. Advantages would be improved visibility, aerodynamics and reduced emissions. Moreover, CMS provides designers with the delicate and potentially detrimental alternatives regarding the placement of rear-view cameras and display monitors. Thus far, research has focused on monitor placement and field of view. Only one study has highlighted technical advantages of altered camera positions (Fornell Fagerström & Gardlund, 2012). The aim of our project is to investigate how altered camera positions affect drivers‘ rearward perception. In a first study, we placed a camera in different positions outside a vehicle and hypothesized that a higher camera position results in stronger visual compression of perceived distance, in particular in exocentric judgments. However, placing the camera further to the front or back of the vehicle should not affect distance estimates.
... In another study, Van They found only small effects in terms of speed underestimation for higher camera positions. 159 Similar results are observable when drivers have to judge their own speed while driving in 160 larger vehicles: ego-speed is underestimated when seated in a van or truck, as compared to a 161 sedan (Panerai, et al., 2001;Rudin-Brown, 2004). However, these results might also be 162 attributable to an increased feeling of safety when driving with a large vehicle and give no 163 direct information about the perception of distance. ...
Article
Objective This study investigates the effects of different positions of side-mounted rear-view cameras on distance estimation of drivers. Background Camera-monitor systems bring advantages as compared to conventional rear-view mirrors, such as improved aerodynamics and enlarged field-of-view. Applied research has mainly focused on the comparison between cameras and mirrors or on positioning of in-vehicle monitors. However, the positioning of the exterior camera awaits investigation given that the perspective of the observer at does affect depth perception at large. Method In two experiments, a total of 50 students estimated metric distances to static vehicles presented in realistic or 3D-rendered pictures. The pictures depicted the rearward scene of a car following the driver as viewed through a camera at varying vertical and horizontal positions. The following vehicle’s size and environmental information varied among conditions and experiments. Results Lower camera positions led to distance overestimation and higher positions to underestimation. The effect increased as the distance to the following vehicle decreased. Moreover, larger vehicles led to stronger distance underestimation, especially in low camera positions. Interestingly, the main effect of camera position disappeared when the ego-vehicles’ back was visible. Conclusion Different rearward viewpoints affect distance estimation of drivers, especially in close distances. However, a visible reference of one’s own vehicle seems to mostly compensate this effect. Application In general, the rear-view camera should be mounted rather higher and to the front of the vehicle. Also, the vehicle’s back should always be visible. Low camera positions are not recommended.
... However, that same study did not find that larger vehicles like SUVs were driven faster in "normal conditions". In a driving simulator study, younger drivers were found to drive faster when their seat height (distance off the ground) was manipulated to replicate a sport utility vehicle (SUV) height as compared to a sports car height (Rudin-Brown, 2004). The effect of vehicle seat height on the processing of visual information to determine a "comfortable speed", although not always perceptible to the drivers, could have serious road safety implications. ...
Article
RÉSUMÉ Le but de cette étude était d’examiner si le type de véhicule, catégorisé en fonction de la taille (voiture vs autre : camion, fourgonnette, véhicule utilitaire sport), avait une influence sur la propension à faire des excès de vitesse, sur l’accélération et les habitudes de freinage des conducteurs et conductrices plus âgés (70 ans et plus), dans le cadre d’une étude longitudinale canadienne. L’hypothèse principale était que les personnes âgées conduisant de plus gros véhicules (p. ex. camions, VUS ou fourgonnettes) seraient plus susceptibles de faire des excès de vitesse que celles conduisant des voitures. Un dispositif enregistrant la conduite avait été installé dans les véhicules des participants (n = 493). Les résultats suggèrent que le type de véhicule conduit a eu peu ou pas d’impact sur le pourcentage de temps passé en excès de vitesse, ou sur les schémas de freinage et d’accélération des conducteurs âgés. Étant donné que la propension à dépasser la limite de vitesse était élevée chez ces conducteurs âgés, quel que soit le type de véhicule, les recherches futures devraient examiner l’effet de ce comportement sur la sécurité routière des conducteurs âgés.
... This is exactly the reason that a person in a truck thinks he drives much slower than driving in a passenger car at the same speed. Evidence suggests that drivers of Sport Utility Vehicles (SUVs) and minivans are driving faster than drivers of regular passenger cars when they are asked to drive at a motorway speed at which they feel comfortable and safe (Rudin-Brown, 2004). In the ultimate case of sitting in an airplane the ratio is about 0.03, that is why it looks as if one is moving rather slowly relative to the ground surface. ...
... Although this effect is typically explained by other, higher-level factors, our study suggests that the rich detail landscapes might cause internal time to run faster due to the higher number of changes, causing participants to drive slower to keep their subjective speed at comfortable levels. A similar finding that links the subjective perception of speed with interval timing is reported in Rudin-Brown (2004) who has shown that eye height of a driver affects preferred speed, with drivers seated higher preferring faster speeds caused by the subjectively slower movement of the outside world. As suggested by a reviewer, an elegant test that could provide further links between laboratory tasks and task-settings with higher external validity is to compare conditions with meaningful semantic visual context versus phase-scrambled movies, which would make the current experiment better comparable to laboratory studies in which semantically irrelevant movement is provided. ...
Article
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The last decades have seen a surge in research into interval timing (for recent reviews, see Merchant et al., 2013; Wittmann, 2013; Allman et al., 2014; van Rijn et al., 2014), with some work focussing on the more abstract mechanisms underlying interval timing (e.g., Taatgen et al., 2007) or the role of cognitive faculties such as memory and decision processes on interval timing tasks (e.g., Taatgen and van Rijn, 2011; Shi et al., 2013), but a large proportion of the work focuses the neural substrates of human (e.g., Kononowicz and van Rijn, 2011; Wiener et al., 2012; Kononowicz and Van Rijn, 2014) and animal (e.g., Diaz-Mataix et al., 2013; Bartolo et al., 2014; Cheng et al., 2014) timing processes. Based on this work, we are getting closer to unraveling the biological mechanisms underlying interval timing.
... A possible explanation for their greater deceleration and acceleration at the 90 degree turn relates to effect of driver height on speed perception. Brown (2004) manipulated vehicle height in a simulator task to examine whether sitting higher (as in an SUV) led to a different choice of speed, in the absence of a speedometer. She found that drivers drove faster in higher vehicles. ...
Article
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Vehicle rollover is the most common characteristic of 4WD (4-Wheel-Drive) crashes. Among all fatal crashes in Australia, a significantly higher proportion of 4WD vehicles were involved in rollovers compared with passenger cars (35 per cent and 13 per cent respectively) (ATSB, 2001). 4WDs are particularly over-represented in rollover crashes in both high- and low-speed zones (ATSB, 2001). While 4WD vehicles have (on average) different physical characteristics to passenger cars, it is also asserted that driver behaviour plays a role in the differential crash patterns of these vehicles. To our knowledge, no systematic empirical research has been undertaken to examine behavioural factors that contribute to 4WD crashes. The effects of vehicular type on driving behaviour are relatively unexplored. This paper presents the preliminary results of a larger pilot project on the investigation of the behaviour of 4WD vehicle drivers in terms of driving performance on the road as measured with Intelligent Transport Systems (ITS). We compared the vehicle dynamics between 4WD and sedan driving. The study involved experienced drivers (N=16) who drove a 4WD and a sedan on a selected route (24 km) for 30 minutes in Brisbane suburban areas. Both vehicles were fitted with technology which passively measured driver performance characteristics such as following distance, direction of gaze, acceleration and deceleration, lateral forces and vehicle speed. The results showed a tendency for drivers to travel faster in the 4WD, and to decelerate and accelerate more rapidly at a 90 degree turn.
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Objective: This study aims to address the limitations of using historical crash data and trajectory data for crash and conflict identification. Specifically, it focuses on enhancing real-time conflict identification by investigating the influence of traffic flow state variables and their interactions on conflicts. Methods: Vehicle trajectory data from HighD were processed, allowing extraction of traffic flow state and corresponding conflict during a specific time interval (10 s). Logistic regression models were further used to verify the impact of variables, including interaction terms, on the conflicts for different lane categories (inner, middle, and outer lanes). Additionally, machine learning techniques were employed to compare conflict identification performance including or excluding variable interactions. Results: The interaction terms of the traffic flow state variables have significant effects on the conflicts for different categories of lanes. It is therefore essential to consider both the individual effects of traffic variables and their interaction effects to analyze conflict risk. Considering variable interactions leads to improved conflict identification accuracy and reduced identification error rates in comparison to the condition where interaction items are not taken into account. Conclusions: The interaction terms of traffic flow state variables significantly affect and enhance conflict identification, improving accuracy and reducing error rates. These findings contribute to advancing the high-precision identification of real-time conflict identification, with implications for improving road safety measures.
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Selecting a safe gap before merging into the traffic is a crucial driving skill that relies on images provided by rear-view mirrors or, recently, camera-monitor systems. When using these visual aids, some drivers select dangerously small gaps to cut in front of faster vehicles. They may do so because they base their decision either on information about distance or object size, or on miscalculated information about time-to-passage (TTP). Previous experiments have been unable to compare the role of TTP, speed, and distance information for drivers’ gap selection, as they did not investigate them in the same experimental regime. The present experiments seek to determine the perceptual variables that guide drivers’ rearward gap selection. Using short videos of an approaching vehicle filmed from three different camera heights (low, conventional, high), a total of 61 subjects either made gap safety decisions (Experiment I), or estimated the TTP, speed, and distance of an approaching vehicle (Experiment II). An effect of camera height was found for gap selection, TTP, and distance estimation, but not for speed estimation. For the high camera position, smaller gaps were selected as safe, TTP estimates were longer, and the distance to the approaching vehicle was perceived as farther. An opposite pattern was found for the low camera. Regression analyses suggested that distance is an important player. The subjects strongly relied on distance information when estimating TTP, and perceived distance dominated subjects’ gap selection. Thus, drivers seem to employ distance-based strategies when selecting safe gaps in rear-view mirrors or monitors.
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Objective: This experiment provides a first-of-its-kind driving-simulator study to investigate the feasibility of camera-monitor systems (CMS) with displaced side-mounted cameras in sedans. Background: Among the increasing number of studies investigating the replacement of side-mounted rearview mirrors with CMS, the placement of side-mounted cameras has been largely neglected. Moreover, user preferences with respect to camera placement have not been validated in a driving simulator. Past research merely has shown that the vertical camera position can affect distance perception. Method: In a driving simulator experiment, we investigated the effects of rearward camera placement on driver acceptance and performance. Thirty-six participants performed multiple lane changes in a last safe-gap paradigm. The camera position, ego-velocity, and velocity of the approaching vehicle varied across the experiment. Results: The results suggest a clear preference for a high rearward perspective, whereas participants disliked the lower viewpoint. However, these stark differences were only marginally mirrored in lane change performance. Average safety margins tended to decrease and their variation tended to increase for the low camera position. Conclusion: Even if the impact of the camera position on driving behavior seems to be small in sedans, driver expectations show clear-cut preferences. When designing CMS, this should be taken into account, as these preferences could promote the use of CMS and thus their positive impact on safety. Application: Designers should place side-mounted cameras as high as possible to increase acceptance of CMS. Low camera positions are not recommended, as they might decrease safety margins and are not appreciated by drivers.
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A constantly increasing number of deaths on roads forces analysts to search for models that predict the driver’s propensity for road traffic accidents (RTAs). This paper aims to examine a relationship between the speed and space assessment capabilities of drivers in terms of their association with the occurrence of RTAs. The method used for this purpose is based on the implementation of the interval Type-2 Fuzzy Inference System (T2FIS). The inputs to the first T2FIS relate to the speed assessment capabilities of drivers. These capabilities were measured in the experiment with 178 young drivers, with test speeds of 30, 50, and 70 km/h. The participants assessed the aforementioned speed values from four different observation positions in the driving simulator. On the other hand, the inputs of the second T2FIS are space assessment capabilities. The same group of drivers took two types of space assessment tests—2D and 3D. The third considered T2FIS sublimates of all previously mentioned inputs in one model. The output in all three T2FIS structures is the number of RTAs experienced by a driver. By testing three proposed T2FISs on the empirical data, the result of the research indicates that the space assessment characteristics better explain participation in RTAs compared to the speed assessment capabilities. The results obtained are further confirmed by implementing a multiple regression analysis.
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The successful creation of telepresence and virtual environments requires a change in design paradigm. We must move away from attempts to recreate reality in its entirety toward the creation of environments that are psychologically real for humans, because in fact, reality mediated through display devices is largely subjective. The experiments discussed in this paper show that a single intrinsic physical property, such as the velocity or stability of a vehicle, can give rise to a multitude of subjective perceptions-for example, that the vehicle is moving faster than it really is, or that it is more likely to tip over going into a turn. These perceptions can easily be manipulated through knowledge of the variables and relationships involved, such as the effect of camera height. Designers can use this knowledge to create systems that promote desirable behaviors and limit dangerous or unproductive behaviors.
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Originally assumed to be work vehicles, cargo vans and pickup trucks under 8,500 pounds (by gross-vehicle weight rating) have been classified as light-duty trucks (LDTs). Due to structural similarities, minivans and sport utility vehicles (SUVs) also have been classified this way, rather than as passenger cars. In the United States, an LDT classification affords a vehicle many regulatory benefits, including lower fuel economy requirements, higher tailpipe and evaporative emissions, avoidance of luxury-goods taxes, and lesser safety standards (including bumper, braking-distance, and interior padding standards). Production and purchase trends suggest that Americans have shifted toward significantly higher use of LDTs for personal travel. Using the 1995 NPTS data set, this research explores the subtle differences in ownership and use patterns between LDTs and passenger cars owned by American households. Based on a variety of model specifications and response variables, the results suggest...
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This study examines potential mappings between the subjective experience of speed when mediated through visual display devices and the physical velocity of a vehicle, especially when the apparatus for experiencing speed and the actual vehicle are not in the same scale. Such mappings are important for creating psychological reality in telepresence environments, such as a driving simulator. Subjects made magnitude estimations of perceived speed by watching video clips of forward motion taken from vehicles of two different heights. A 2.625:1 ratio in “virtual” eyeheights was approximately maintained in the magnitude estimates, indicating that speed is experienced as a scaled quantity relative to virtual eyeheight. When magnitude estimates for the lower virtual eyeheight were scaled, perceived speed at that height could be predicted for any actual velocity in this experiment. Building on this knowledge, telepresence designers must account for the scale factor in predicting other behaviors such as distance for braking and turning the vehicle.
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A highway driving simulator with a computer-generated visual display, physical motion cues of roll, yaw, and lateral translation, and velocity-dependent sound/vibration cues was used to investigate the influence of these cues on driver performance. Forty-eight student subjects were randomly allocated to six experimental groups. Each group of eight subjects experienced a unique combination of the motion and audio cues. The control group received a full simulation condition while each of the remaining five groups performed with certain combinations of motion and sound deleted. Each driver generated nine minutes of continuous data from which five performance measures were derived. Results indicate that the performance measures of yaw, lateral, and velocity deviation are significantly affected by the deletion of cues. In support of the hypothesis that driver performance is augmented by the addition of motion cues, statistically significant negative correlations were obtained between the number of motion cues present and the measures of yaw and lateral deviation. With respect to motion and audio cues, recommendations are made regarding simulator design criteria.
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It may be labeled sport utility vehicle, SUV, sport-ute, suburban assault vehicle, or a friend of OPEC (Organization for Petroleum Exporting Countries). It has been the subject of comics, the object of high-finance marketing ploys, and the theme of Dateline. Whatever the label or the occasion, this vehicle is in great demand. The popularity of sport utility vehicles (SUVs) has increased dramatically since the late 1970s, and SUVs are currently the fastest growing segment of the motor vehicle industry. Hoping to gain market share due to the popularity of the expanding SUV market, more and more manufacturers are adding SUVs to their vehicle lineup. One purpose of this study is to analyze the world of the SUV to determine why this vehicle has seen such a rapid increase in popularity. Another purpose is to examine the impact of SUVs on energy consumption, emissions, and highway safety.
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Typescript. Thesis (Ph. D.)--University of Iowa, 1995. Includes bibliographical references (leaves 167-172).
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