Motion extrapolation of car-following scenes in younger and older drivers

OBJECTIVE: The objective was to determine whether distortions occur in motion extrapolation of car-following scenes in younger and older drivers. BACKGROUND: Drivers cannot see an entire traffic scene clearly with one glance. They must extrapolate the motion of surrounding vehicles while scanning other parts of the scene. Further, abilities relevant to motion extrapolation decline with age. Thus, it is important to evaluate age differences in motion extrapolation. METHOD: Displays simulated car-following scenes. After an interruption, the scene reappeared at the correct position in its trajectory or at a position that was more advanced or less advanced than the correct position. Drivers reported whether the scene reappeared at the correct position. RESULTS: When the virtual self moved faster than the lead car, older drivers' judgments were biased toward less advanced reappearance positions. Younger drivers' judgments were biased toward more advanced positions. The implication is that older drivers extrapolated the motion slower than did younger drivers. CONCLUSION: Distortions occurred in motion extrapolation of car-following scenes, and age differences occurred in such distortions. APPLICATION: Potential applications of this research include traffic safety. Age differences in motion extrapolation are useful to consider in differential accident patterns of younger and older drivers. Future research should investigate the relationship between accidents and the ability to extrapolate motion, particularly during driver distractions.     

Profiles in driver distraction: effects of cell phone conversations on younger and older drivers

Our research examined the effects of hands-free cell phone conversations on simulated driving. We found that driving performance of both younger and older adults was influenced by cell phone conversations. Compared with single-task (i.e., driving-only) conditions, when drivers used cell phones their reactions were 18% slower, their following distance was 12% greater, and they took 17% longer to recover the speed that was lost following braking. There was also a twofold increase in the number of rear-end collisions when drivers were conversing on a cell phone. These cell-phone-induced effects were equivalent for younger and older adults, suggesting that older adults do not suffer a significantly greater penalty for talking on a cell phone while driving than compared with their younger counterparts. Interestingly, the net effect of having younger drivers converse on a cell phone was to make their average reactions equivalent to those of older drivers who were not using a cell phone. Actual or potential applications of this research include providing guidance for recommendations and regulations concerning the use of mobile technology while driving.     

Eye movements and industrial inspection

A brief survey is given of the eye movement parameters which contribute to visual search strategies. The literature on eye movements and industrial inspection is reviewed and some recent studies carried out at the University of Birmingham into the eye movements underlying four inspection tasks are described. These tasks included the inspection of tin cans, electrical edge connectors, men's briefs and woven fabric.     

Do in-vehicle advanced signs enhance older and younger drivers’ intersection performance? Driving simulation and eye movement results

An experimental study was conducted to determine if intersection behaviour benefited from advanced in-vehicle signs presented to older and younger drivers in a head-up display (HUD) format. The University of Calgary Driving Simulator (UCDS) was used to evaluate intersection performance. Measures of those who were able to stop or ran the yellow light, speed over the span of the intersection, perception response time, and eye movements were analyzed to determine if performance improved or whether undesirable adaptive behaviours occurred. In-vehicle signs facilitated an increase in the frequencies of stopping for both younger and older drivers at intersections with relatively short yellow onsets. The speed at the yellow light onset for both those who stopped and those who proceeded through the intersection was reduced by the presence of the in-vehicle signs. The primary behavioral influence of the in-vehicle signs was to cause the drivers’ to reduce their velocity in advance of an intersection. Eye movement analyses indicated that younger drivers looked at the in-vehicles signs more often and for longer overall durations than older drivers. Older drivers had slower intersection approach speeds, stopped more accurately, and were more likely to not clear the intersection before the traffic light turned to an all-red phase than younger drivers. The implications of the in-vehicle sign results are discussed in terms of in-vehicle information systems (IVIS) design guidelines and evaluation methods.     

Visual requirements for safety and mobility of older drivers.

Efforts to assess visual deterioration with increasing age, coupled with new mechanisms proposed to limit the exposure of visually impaired drivers to driving risks, have emerged in response to the increase in older drivers. Visual functions discussed in this context include static acuity (photopic, mesopic, and in the presence of glare), dynamic visual acuity, visual field, contrast sensitivity, and motion perception. Exposure control mechanisms discussed include alternative periodic vision testing strategies, visual training, and environmental and vehicular modifications to accommodate the older driver. Finally, relevant research needs are addressed.     

Liability of older drivers in collisions

Abstract

Type of collision, age, and liability were ascertained for nearly 1500 drivers involved in two-car collisions. The over-involvement ratio (i.e. the ratio of the number of liable to the number of non-liable drivers) was higher for drivers younger than 23 years old, or older than 50 years old, compared with the 23-49-year-old group. An analysis of the over-involvement ratio of the different age-groups within each type of collision did not point to some types of collision as especially important causes of the high over-involvement ratio of older persons. However, collisions with oncoming cars when turning left are an exception. This study largely confirms an earlier one by the same author.     

Self-reported visual problems of older drivers

We conducted a survey in order to gain insights into the reasons older persons decide to give up driving. Our survey focused on vision. We probed the relationship between visual deficiencies and driving status by asking older people about the problems they encountered while performing routine visual tasks. The results showed that older persons who had recently given up driving reported more visual problems than did their driving counterparts. These problems related to difficulties in dynamic vision, visual processing speed, visual search, light sensitivity, and near vision. The results suggested that older persons are sensitive to their own visual deficits and that this awareness influences decisions about driving.     

Repetition improves older and younger adult memory for automated appointment messages.

Automated telephone messaging systems have dramatically expanded communication about health service appointments, but few studies have directly investigated these messages. The present study investigated whether message repetition (1, 2, or 3 presentations) and listener age (mean age = 71 or 19 years) improved memory for automated appointment messages. Repetition improved older and younger adult memory for appointment information. Moreover, 2 presentations reduced age differences in accuracy of answering questions about the messages. This was not the case for free recall, suggesting that older adults differentially benefited from repetition only when provided with additional retrieval support. These findings show that older as well as younger adults benefit from at least 1 repetition of appointment messages. Actual or potential applications of this research include the use of repetition to improve comprehension of automated telephone messages.     

Eye movements in software traceability link recovery

Information Retrieval (IR) approaches, such as Latent Semantic Indexing (LSI) and Vector Space Model (VSM), are commonly applied to recover software traceability links. Recently, an approach based on developers’ eye gazes was proposed to retrieve traceability links. This paper presents a comparative study on IR and eye-gaze based approaches. In addition, it reports on the possibility of using eye gaze links as an alternative benchmark in comparison to commits. The study conducted asked developers to perform bug-localization tasks on the open source subject system JabRef. The iTrace environment, which is an eye tracking enabled Eclipse plugin, was used to collect eye gaze data. During the data collection phase, an eye tracker was used to gather the source code entities (SCE’s), developers looked at while solving these tasks. We present an algorithm that uses the collected gaze dataset to produce candidate traceability links related to the tasks. In the evaluation phase, we compared the results of our algorithm with the results of an IR technique, in two different contexts. In the first context, precision and recall metric values are reported for both IR and eye gaze approaches based on commits. In the second context, another set of developers were asked to rate the candidate links from each of the two techniques in terms of how useful they were in fixing the bugs. The eye gaze approach outperforms standard LSI and VSM approaches and reports a 55 % precision and 67 % recall on average for all tasks when compared to how the developers actually fixed the bug. In the second context, the usefulness results show that links generated by our algorithm were considered to be significantly more useful (to fix the bug) than those of the IR technique in a majority of tasks. We discuss the implications of this radically different method of deriving traceability links. Techniques for feature location/bug localization are commonly evaluated on benchmarks formed from commits as is done in the evaluation phase of this study. Although, commits are a reasonable source, they only capture entities that were eventually changed to fix a bug or resolve a feature. We investigate another type of benchmark based on eye tracking data, namely links generated from the bug-localization tasks given to the developers in the data collection phase. The source code entities relevant to subjected bugs recommended from IR methods are evaluated on both commits and links generated from eye gaze. The results of the benchmarking phase show that the use of eye tracking could form an effective (complementary) benchmark and add another interesting perspective in the evaluation of bug-localization techniques.     

Perception-response speed and driving capabilities of brain-damaged and older drivers

Three experiments including reaction time (RT) tasks and driving tasks were conducted to identify variables that may be sensitive to the effects of brain damage or aging and to determine how RT tasks relate to driving performance. In Experiment 1 mean RTs of the brain-damaged and older subjects disproportionately increased relative to those of controls, with increasing difference between subsequent compound stimuli. In Experiment 2 response accuracy of brain-damaged subjects deteriorated more than that of controls when the similarity of a task to actual driving increased. In Experiment 3 brain-damaged patients were slower and less accurate than the controls on all measures of a platoon car-following task, whereas the older subjects were only less accurate. Compared with those of the controls, brake RTs of neither the older subjects nor the patients were disproportionately affected by increasing task load. Performance on the platoon driving task could be successfully predicted by a laboratory RT task on time estimation only for the brain-damaged subjects.     

Identification of vehicle design requirements for older drivers

The proportion of older people in the population is rising, as is the proportion of older women driving licence holders. The needs and abilities of older drivers therefore need to be considered in vehicle design. Following some initial focus groups an extensive nation-wide postal survey was conducted to ascertain the type and degree of problems associated with automotive design for older drivers and to guide further research into the most appropriate areas. Over a thousand questionnaires were received. Findings indicate that particular difficulties are experienced significantly more often by older drivers than younger drivers, in particular turning to look out of the rear window and getting in and out of the car. Reasons for these were ascertained and are reported here. The findings have guided a subsequent research project into the factors affecting ease of entry and exit by older drivers.     

Designing an information search interface for younger and older adults

OBJECTIVE: The present study examined Web-based information retrieval as a function of age for two information organization schemes: hierarchical organization and one organized around tags or keywords. BACKGROUND: Older adults' performance in information retrieval tasks has traditionally been lower compared with younger adults'. The current study examined the degree to which information organization moderated age-related performance differences on an information retrieval task. The theory of fluid and crystallized intelligence may provide insight into different kinds of information architectures that may reduce age-related differences in computer-based information retrieval performance. METHOD: Fifty younger (18-23 years of age) and 50 older (55-76 years of age) participants browsed a Web site for answers to specific questions. Half of the participants browsed the hierarchically organized system (taxonomy), which maintained a one-to-one relationship between menu link and page, whereas the other half browsed the tag-based interface, with a many-to-one relationship between menu and page. This difference was expected to interact with age-related differences in fluid and crystallized intelligence. RESULTS: Age-related differences in information retrieval performance persisted; however, a tag-based retrieval interface reduced age-related differences, as compared with a taxonomical interface. CONCLUSION: Cognitive aging theory can lead to interface interventions that reduce age-related differences in performance with technology. In an information retrieval paradigm, older adults may be able to leverage their increased crystallized intelligence to offset fluid intelligence declines in a computer-based information search task. APPLICATION: More research is necessary, but the results suggest that information retrieval interfaces organized around keywords may reduce age-related differences in performance.     

The changing construct of computer anxiety for younger and older adults

A revalidation of a previously developed computer anxiety scale (Marcoulides, 1989) indicated changes in the factor structure for both younger and older adults. Two factors emerged — Direct and Indirect Involvement with computers — as compared with the previous two factors of General Computer Anxiety and Equipment Anxiety. This suggests that the construct of computer anxiety may have changed, perhaps because of the rapid changes in computers and the technological environment. Additional results showed that, while the factor structure was similar for younger and older adults, two items differentially loaded on the two factors. These results suggest the need for further examination of computer anxiety with older adults, with the possibility of developing computer anxiety scales specifically for older adults.     

Visual difficulties reported by low-vision and nonimpaired older adult drivers

Nonimpaired and low-vision older adults responded to a questionnaire regarding the types of visual difficulties experienced while performing daily tasks and while driving. Using the factors produced from a factor analysis as predictors, a discriminant analysis was performed to determine whether significant differences in visual problems existed between the groups. The majority of participants reported that they currently required more time than in the past to perform tasks that depended on their vision, regardless of their visual status. All participants reported experiencing significant difficulties with static and dynamic acuity, peripheral vision, illumination problems, and contrast sensitivity. Both nonimpaired and low-vision older adult drivers reported experiencing difficulty with glare, peripheral vision, and night driving. Low-vision drivers reported experiencing unique difficulties with near acuity, distant acuity, and physical obstructions. Potential applications of this research include suggestions for redesigning automobiles and highway signs for safer use and viewing.     

Positive display polarity is advantageous for both younger and older adults

The effect of display polarity on visual acuity and proofreading performance was investigated for younger and older adults. An advantage of positive polarity (dark characters on light background) over negative polarity (light characters on dark background) was expected for younger adults, but the effects on older adults were ambiguous. Light scatter due to residues in the senescent lens and vitreous humour could reverse the typical advantage of positive polarity. However, age-related changes lead to a decline in retinal illuminance. Brighter positive polarity displays should help to compensate for this decline and, accordingly, lead to better performance than darker negative polarity displays. Participants conducted a visual acuity test with black optotypes on white background or white optotypes on black background and performed a proofreading task in the same polarity. A positive polarity advantage was found for both age groups. The presentation in positive polarity is recommended for all ages.

Practitioner summary: In an ageing society, age-related vision changes need to be considered when designing digital displays. Visual acuity testing and a proofreading task revealed a positive polarity advantage for younger and older adults. Dark characters on light background lead to better legibility and are strongly recommended independent of observer's age.     

Gait parameters as predictors of slip severity in younger and older adults

This study investigated the association between slip severity and pre-slip gait characteristics of younger and older subjects. Sixteen younger and eleven older healthy adults walked onto an unexpectedly slippery surface. Slip severity was categorized as either hazardous or non-hazardous using a 1.0 ms peak slip velocity threshold. The results showed that hazardous slips were associated with greater step lengths (normalized by leg length) (SLR), larger and more rapidly changing foot – floor angles (FFA) at heel strike, and increased cadence across the two subject groups. Older subjects were found to walk with shorter SLR and with smaller and more slowly changing FFA at heel strike compared to younger subjects. However, both younger and older subjects experienced hazardous slips at the same rate. A logistic regression model relating SLR and cadence to slip severity predicted that increased SLR and decreased cadence would result in increased probability of hazardous slip (R² = 0.45, χ² = 15.30, p<0.01). A second logistic regression model relating FFA with slip severity predicted that increased FFA would result in increased probability of hazardous slip (R² = 0.53, χ² = 16.55, p<0.01). These results suggest that gait characteristics prior to foot contact play an important role in the severity of an ensuing slip. The finding that older adults experienced hazardous slips at the same rate as young adults even though their SLR and FFA are smaller suggests that age is also playing a role in other aspects of postural control that impact slip severity.     

Eye movements and visual discomfort when viewing stereoscopic 3D content

The visual brain fuses the left and right images projected onto the two eyes from a stereoscopic 3D (S3D) display, perceives parallax, and rebuilds a sense of depth. In this process, the eyes adjust vergence and accommodation to adapt to the depths and parallax of the points they gazed at. Conflicts between accommodation and vergence when viewing S3D content potentially lead to visual discomfort. A variety of approaches have been taken towards understanding the perceptual bases of discomfort felt when viewing S3D, including extreme disparities or disparity gradients, negative disparities, dichoptic presentations, and so on. However less effort has been applied towards understanding the role of eye movements as they relate to visual discomfort when viewing S3D. To study eye movements in the context of S3D viewing discomfort, a Shifted-S3D-Image-Database (SSID) is constructed using 11 original nature scene S3D images and their 6 shifted versions. We conducted eye-tracking experiments on humans viewing S3D images in SSID while simultaneously collecting their judgments of experienced visual discomfort. From the collected eye-tracking data, regions of interest (ROIs) were extracted by kernel density estimation using the fixation data, and an empirical formula fitted between the disparities of salient objects marked by the ROIs and the mean opinion scores (MOS). Finally, eye-tracking data was used to analyze the eye movement characteristics related to S3D image quality. Fifteen eye movement features were extracted, and a visual discomfort predication model learned using a support vector regressor (SVR). By analyzing the correlations between features and MOS, we conclude that angular disparity features have a strong correlation with human judgments of discomfort.