Choice of time-headway in car-following and the role of time-to-collision information in braking

Time-headway (THW) during car-following and braking response were studied in a driving simulator from the perspective that behaviour on the manoeuvring level (e.g. choice of THW) may be linked to operational competence of vehicle control (e.g. braking) via a process of adaptation. Time-headway was consistent within drivers and constant over a range of speeds. Since time-headway represents the time available to the driver to reach the same level of deceleration as the lead vehicle in case it brakes, it was studied whether choice of time-headway was related to skills underlying braking performance. The initiation and control of braking were both affected by time-to-collision (TTC) at the moment the lead vehicle started to brake. This strongly supported the idea that time-to-collision information is used for judging the moment to start braking and in the control of braking. No evidence was found that short followers differ from long followers in the ability to accurately perceive TTC. There was, however, evidence that short followers are better able to programme the intensity of braking to required levels. Also, short followers tuned the control of braking better to the development of criticality in time during the braking process. It was concluded that short followers may differ from long followers in programming and execution of the braking response.     

Visual processing impairment and risk of motor vehicle crash among older adults

CONTEXT: Motor vehicle crash risk in older drivers has been associated with visual acuity loss, but only weakly so, suggesting other factors contribute. The useful field of view is a measure that reflects decline in visual sensory function, slowed visual processing speed, and impaired visual attention skills. OBJECTIVE: To identify whether measures of visual processing ability, including the useful field of view test, are associated with crash involvement by older drivers. DESIGN: Prospective cohort study with 3 years of follow-up, 1990-1993. SETTING: Ophthalmology clinic assessment of community-based sample. PATIENTS: A total of 294 drivers aged 55 to 87 years at enrollment. MAIN OUTCOME MEASURE: Motor vehicle crash occurrence. RESULTS: Older drivers with a 40% or greater impairment in the useful field of view were 2.2 times (95% confidence interval, 1.2-4.1) more likely to incur a crash during 3 years of follow-up, after adjusting for age, sex, race, chronic medical conditions, mental status, and days driven per week. This association was primarily mediated by difficulty in dividing attention under brief target durations. CONCLUSION: Reduction in the useful field of view increases crash risk in older drivers. Given the relatively high prevalence of visual processing impairment among the elderly, visual dysfunction and eye disease deserve further examination as causes of motor vehicle crashes and injury.     

Effects of age, system experience, and navigation technique on driving with an advanced traveler information system

This paper explores the effects of age, system experience, and navigation technique on driving, navigation performance, and safety for drivers who used TravTek, an Advanced Traveler Information System. The first two studies investigated various route guidance configurations on the road in a specially equipped instrumented vehicle with an experimenter present. The third was a naturalistic quasi-experimental field study that collected data unobtrusively from more than 1200 TravTek rental car drivers with no in-vehicle experimenter. The results suggest that with increased experience, drivers become familiar with the system and develop strategies for substantially more efficient and safer use. The results also showed that drivers over age 65 had difficulty driving and navigating concurrently. They compensated by driving slowly and more cautiously. Despite this increased caution, older drivers made more safety-related errors than did younger drivers. The results also showed that older drivers benefited substantially from a well-designed ATIS driver interface.     

Prospective memory and apolipoprotein e in healthy aging and early stage Alzheimer's disease.

The present study examined whether prospective memory performance discriminates healthy aging from very mild dementia of the Alzheimer type (DAT) and individuals at risk for DAT because of the presence of the apolipoprotein E (ApoE) ε4 allele. Four groups (young subjects, young-old control subjects, old-old control subjects, and subjects with very mild DAT) engaged in an event-based prospective memory task wherein they responded to a specific word embedded in a general knowledge test. Results indicated that prospective memory performance was clearly impaired in the very mild DAT group relative to the healthy older control groups. Moreover, prospective memory performance appears to capture unique variance in discriminating these 2 groups above and beyond standard retrospective memory tests. However, prospective memory was not affected by ApoE status in the young-old control group and, contrary to predictions, the ε4+ old-old control subjects showed better performance than did the ε4- subjects. In contrast to the healthy individuals, in the very mild DAT group, ε4+ subjects showed deficits in performance relative to the ε4- subjects. Discussion focuses on prospective memory as a cognitive indicator of early stage DAT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Observed child restraint use in automobiles

Visual observations were made on restraint use in occupants of 5,050 automobiles containing at least one passenger less than 10 years of age, and short interviews were conducted with the drivers. Ninety-three percent of passengers less than 10 years old were not restained. Eighty-nine percent of passengers 10 or older and 78% of the drivers were not restained. Sixteen percent of child motor vehicle restraint devices observed were not used, and 73% of those in use were not used correctly. Use of such devices declined sharply after age 1. Although child passengers were more likely to be restained if the driver was restrained, more than 75% of the children were not restrained when the driver was, even if the driver was the child's parent.     

Influence of visual control, conduction, and central integration on static and dynamic balance in healthy older adults

Aging is associated with decreased balance abilities, resulting in an increased risk of fall. In order to appreciate the visual, somatosensory, and central signals involved in balance control, sophisticated methods of posturography assessment have been developed, using static and dynamic tests, eventually associated with electromyographic measurements. We applied such methods to a population of healthy older adults in order to appreciate the respective importance of each of these sensorial inputs in aging individuals. Posture control parameters were recorded on a force-measuring platform in 41 healthy young (age 28.5 +/- 5.9 years) and 50 older (age 69.8 +/- 5.9 years) adults, using a static test and two dynamic tests performed by all individuals first with eyes open, then with eyes closed. The distance covered by the center of foot pressure, sway area, and anteroposterior oscillations were significantly higher, with eyes open or closed, in older people than in young subjects. Significant differences were noted in dynamic tests with longer latency responses in the group of old people. Dynamic recordings in a sinusoidal test had a more regular pattern when performed eyes open in both groups and evidenced significantly greater instability in old people. These data suggest that vision remains important in maintaining postural control while conduction and central integration become less efficient with age.     

Impact of the 1970 legal BAC 0.05 mg% limit legislation on drunk-driver-involved traffic fatalities, accidents, and DWI in Japan

Official statistics of motor vehicle fatality data have indicated that alcohol involvement in fatal crashes has declined substantially in Japan since 1970. The national campaign against drunken driving in Japan provides a natural experiment in which to test the predictions of deterrence theory. Utilizing official data over the 1960-1995 period, we report conclusive evidence that 1970s legislation is having a measurable and long-term effect on alcohol-related motor vehicle fatalities. Enactment of the lower legal blood alcohol limit with a combination of other severe sanctions has been more desirable in the prevention of alcohol-related fatalities in the long term as shown in this study. Further extensive research is necessary to investigate performance at the lower legal limit in other societies in order to inspire a strong "international lobby" to support the reduced legal blood alcohol limit for drivers all over the world, as there is no doubt that a reduction in alcohol-impaired driving will result in a substantial savings of human lives and resource worldwide.     

Mosquito fauna (Diptera:Culicidae) from Falcon State, Venezuela. I. New records and current checklist

A Markov model was used to assess the cost-benefit ratios of six strategies of screening older drivers for mental status, beginning at age 65. Probabilities of motor vehicle collisions (MVCs), injuries, and fatalities were obtained from national data. Dementia prevalence, test characteristics, and costs were obtained from the literature. Costs included lost wages, car ownership, alternative transportation, and injuries. Using a relative risk of MVC for those with dementia of 5 and a 5% annual discounting rate, the average cost per driver ranged from $51,600 (no testing) to $58,400 (testing every five years). The benefit was < one day of life gained, and the benefits of screening cost approximately 2.8 million dollars per life-year gained. Increasing the relative risk from 5 to 20 substantially improved the cost-benefit of mental status screening. However, mental status screening of older drivers would also be cost-beneficial if physician referral costs were lowered to $60 per evaluation. The authors conclude that a dementia screening program for older drivers would be cost-beneficial if physician evaluations were limited or their cost lowered to < or = $60.     

Improved osseointeraction of calcium phosphate-coated external fixation pins. Studies in calves

The analysis of health state of drivers sent for an extra health examination for the estimation of driving capability for the driving of motor vehicle in alcoholic state was presented. The study included 380 drivers who were found driving drunk by traffic police (studied group) and 180 drivers of control group sent for an extra health examination for some other reason. The disorders in psychomotor sphere were noticed in the drivers of studied group and it was determined that they had caused significantly larger number of traffic accidents in last five-year period compared to the drivers of control group. The alcohol consumption in driving population represents significant medical, social, economic and traffic problem. The control of driver's alcoholism, the sending of alcoholic drivers to an extra health examination for the repeated estimation of driving capability and including in therapeutic and health-educational program can present significant measure of the primary prevention of road traffic traumatism which is on the constant increase.     

Improving older drivers' hazard perception ability.

One reason that older drivers may have elevated crash risk is because they anticipate hazardous situations less well than middle-aged drivers. Hazard perception ability has been found to be amenable to training in young drivers. This article reports an experiment in which video-based hazard perception training was given to drivers who were between the ages of 65 and 94 years. Trained participants were significantly faster at anticipating traffic hazards compared with an untrained control group, and this benefit was present even after the authors controlled for pretraining ability. If future research shows these effects to be robust, the implications for driver training and safety are significant. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal change in language production: Effects of aging and dementia on grammatical complexity and propositional content.

Mixed modeling was used to examine longitudinal changes in linguistic ability in healthy older adults and older adults with dementia. Language samples, vocabulary scores, and digit span scores were collected annually from healthy older adults and semiannually from older adults with dementia. The language samples were scored for grammatical complexity and propositional content. For the healthy group, age-related declines in grammatical complexity and propositional content were observed. The declines were most rapid in the mid 70s. For the group with dementia, grammatical complexity and propositional content also declined over time, regardless of age. Rates of decline were uniform across individuals. These analyses reveal how both grammatical complexity and proposition content are related to late-life changes in cognition in healthy older adults as well as those with dementia. Alzheimer's disease accelerates this decline, regardless of age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A physical fitness model of older adults

Physical fitness for young people is viewed as a multidimensional construct, in that it consists of specific components such as strength, mobility, balance, flexibility, and stamina. This study examined whether this structure underlying physical fitness is also relevant to older adults. A 10-item performance test, which was assumed to assess six components of physical fitness, was administered to 69 healthy volunteers ranging in age from 61 to 83 years. A covariance structure model was applied to the test data: the second-order factor was Physical Fitness, and the first-order factors were Strength, Walking, Balance, Flexibility, Stamina, and Manual Speed which were assumed to be measured based on the ten observed variables. Goodness-of-fit index (GFI) of the model was acceptable (GFI = 0.93). While four factors relating to basic motor performances (Strength, Walking, Balance, and Manual Speed) had loadings more than 0.62 to Physical Fitness, Flexibility and Stamina had less than 0.35. It was suggested for elderly people that strength, mobility, balance, and speed components of physical fitness were highly correlated and explainable by a single factor, while flexibility and cardiorespiratory endurance were to be measured by use of specific measures.     

Successful overlapping anal sphincter repair: relationship to patient age, neuropathy, and colostomy formation

OBJECTIVE: Although it is documented that brain dopamine activity declines with age, the functional significance of this is not known. This study assessed the relation between measures of brain dopamine activity and indexes of motor and cognitive function in healthy individuals. METHOD: Thirty healthy volunteers aged 24-86 years were studied with positron emission tomography and [11C]raclopride to assess dopamine D2 receptors. All subjects underwent a neuropsychological test battery that included tasks found to be sensitive to dopamine alterations in patients with neurodegenerative disease and control tasks. RESULTS: Transfer of [11C]raclopride from plasma to brain in the striatum and cerebellum was not affected by age. In contrast, D2 receptor availability in the caudate and putamen declined with age. Correlations between D2 receptors and neuropsychological test performance were strongest for the motor task (Finger Tapping Test) and were also significant for most tasks involving frontal brain regions, including measures of abstraction and mental flexibility (Wisconsin Card Sorting Test) and attention and response inhibition (Stroop Color-Word Test, interference score). These relationships remained significant after control for age effects. CONCLUSIONS: Age-related decreases in brain dopamine activity are associated with a decline in motor function and may also contribute to impaired performance on tasks that involve frontal brain regions. Interventions that enhance dopamine activity may improve performance and quality of life for the elderly. The fact that correlations remained significant after age effects were partialed out suggests that dopamine activity may influence motor and cognitive performance irrespective of age.     

Differences in the functional neuroanatomy of inhibitory control across the adult life span.

Inhibitory control, the ability to suppress irrelevant stimuli, is a fundamental cognitive function that deteriorates during aging, but little is understood about the bases of decline. Thus, we used event-related functional magnetic resonance imaging (fMRI) to study inhibitory control in healthy adults aged 18 to 78. Activation during "successful inhibition" occurred predominantly in right prefrontal and parietal regions and was more extensive, bilaterally, and prefrontally, in the older groups. Presupplementary motor area was also more active in poorer inhibitory performers. Therefore, older adults activate areas that are comparable to those activated by young adults during inhibition, as well as additional regions. The results are consistent with a compensatory interpretation and extend the aging neuroimaging literature into the cognitive domain of inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Illegal parking in handicapped zones: Demographic observations and review of the literature.

Found that the overall rate of illegal parking in a parking space reserved for handicapped persons by a total of 266 drivers was 62.0%. 67.7% of Ss were White, and 85.7% were estimated to be above the age of 25 yrs. Although there were more violations recorded for Whites and older drivers, the percentage of young and Black drivers who were violators was higher than that for Whites and older drivers. Violators tended to remain in the spaces for shorter durations than did legal parkers. Availability of equally convenient, illegal parking alternatives (e.g., fire lanes) appeared to reduce violations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Eye movements of young and older adults during reading.

The eye movements of young and older adults were tracked as they read sentences varying in syntactic complexity. In Experiment 1, cleft object and object relative clause sentences were more difficult to process than cleft subject and subject relative clause sentences; however, older adults made many more regressions, resulting in increased regression path fixation times and total fixation times, than young adults while processing cleft object and object relative clause sentences. In Experiment 2, older adults experienced more difficulty than young adults while reading cleft and relative clause sentences with temporary syntactic ambiguities created by deleting the that complementizers. Regression analyses indicated that readers with smaller working memories need more regressions and longer fixation times to process cleft object and object relative clause sentences. These results suggest that age-associated declines in working memory do affect syntactic processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of aging and schedules of knowledge of results on motor learning

Little research has been conducted on aging and the learning of motor skills. In this study, we examined the effects of different schedules of knowledge of results (KR) on the acquisition and retention of a movement timing task by young adults (20-23 years) and older adults (60-82 years). The results indicated that there were differences between young and older adults in the accuracy and consistency of motor performance when KR was provided. Accuracy effects persisted during a retention interval when KR was no longer provided, although there were no differences in variability. There were no interactions of age with any of the KR-related variables. These findings suggest that the ability to process KR, and the effects of KR on motor learning, are similar in young and older adults. These findings are discussed in terms of age-related issues in movement control and learning processes.     

The utility of placing recollection in opposition to familiarity in early discrimination of healthy aging and very mild dementia of the Alzheimer’s type.

This study explored the ability to control familiarity-based information in a memory exclusion paradigm in healthy young, older adults, and early stage DAT individuals. We compared the predictive power of memory exclusion performance to standard psychometric performance in discriminating between aging and the earliest stage of DAT and between APOe4-present and APOe4-absent genotype in healthy control individuals. Participants responded “yes” to words that were previously semantically encoded, and “no” to words that were previously read aloud and to new words. The number of targets and distractors on the read “distractor” list was manipulated to investigate the degree to which aging and DAT influence the ability to recollect in the face of distractor familiarity due to repetition. Memory exclusion performance was better for healthy older adults than very mild DAT individuals and better for healthy control individuals with APOe4 allele than those without APOe4 allele even after controlling for standard psychometric performance. Discussion focuses on the importance of attentional control systems in memory retrieval and the utility of the opposition paradigm for discriminating healthy versus pathological aging. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Survey of impaired drivers, fatally injured or surviving, who caused fatal highway accidents in Alberta in 1970-72

In 1970-72, 456 (53.4%) of 854 drivers responsible for a motor vehicle accident in which either they or other persons were killed had been drinking beforehand. Of surviving culpable drivers tested for blood alcohol concentration 81.7% were found to be legally impaired; however, only 24.8% of these drivers were tested. Because surviving culpable drivers pose a possible future hazard to highway safety it is important that data on this group be collected and analysed.     

Psychophysiologic sensitization to headlight glare among professional drivers with and without cardiovascular disease.

EEG and cardiovascular (CV) response and recovery to simulated headlight glare (the glare pressor test) were examined in 4 groups of male professional drivers (age 25-52 yrs)—12 with ischemic heart disease (IHD), 12 with hypertension (HTN), 10 with borderline hypertension (BHTN), and 34 who were healthy—and in 23 non-professional driver controls—to assess sensitization to this night driving stressor in relation to degree of CV disease severity. After glare exposure the IHD drivers showed the most pronounced alpha blockade, a rise in diastolic BP (DBP), and, unlike the other groups, a persistent fall in finger pulse volume. The BHTN group reacted initially with DBP rise and finger pulse drop, mainly without CNS arousal. The DBP remained constant in normotensive professional drivers older than 40. The drivers' CV responses to glare were inversely related to reported stressors and subjective experience. Anxiety trait and long work hours were associated with heightened central arousal to glare in professional drivers. Results suggest that there may be progressive degrees of sensitization to glare exposure in these samples, with the least among normotensive professional drivers older than 40, moderate levels in borderline hypertensives, and the most severe in drivers with IHD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)