The overall aim of this thesis is to corroborate whether the Situation Awareness (SA) of older drivers is deficient to that of younger driving groups, due to the onset of age-related cognitive decrements. This is important to ascertain due to a presumed linkage between the concept and accident causation. In addition, the research undertaken to date to investigate this linkage has exclusively utilised rather artificial driving simulators and simulations. Thus there is a need for data from more ecologically valid methods. The research studies reported here have sought to preference on-road assessments (of different complexity), and to capture what information was selectively perceived, comprehended and reacted to; rather than, as in previous work, what was recalled. To achieve this, a Think aloud methodology was chosen to produce narratives of a driver s thoughts. This method was advantageously unobtrusiveness, but also flexible - it could additionally be used to compare an individual's SA to a driving performance measure, Hazard Perception. The driving-based studies undertaken found that for a relatively non-taxing route, an older driver group could produce cohesive awareness in parity with a younger driver group. However, the concepts from which that awareness was based upon drew more on general, direction based, concepts, in contrast to the younger group s focus on more specific, action based, concepts, and rearward and safety-related cues. For a more cognitively taxing route, the younger group produced significantly higher (p < 0.024) individual SA-related scores than their older counterparts. But the concepts/cues both groups relied upon remained similar - particularly in regards to the ratio of those indicative of a rearward and/or a safety-related focus. In a video-based study, however, and in contrast, the older driver group s SA scores improved sufficient to outperform a younger group, but, despite this, not for video-based scores indicative of Hazard Perception (HP). In this latter regard, age-related decrements appeared to be more influential, as the older group felt they were under time pressure during a HP test. However, the difficulty this presented appeared to advantageously bring more attention and effort to the task, which were argued as important factors for the uplift in their SA scoring. The thesis also showed that older groups judgement of the actual complexity of a driving task could potentially be deficient to that of younger driver groups. This could cause problems as incorrect perceptions could deflate the relevance and cohesiveness of information being processing. In contrast, the perceived complexity of a task could bring a rise or fall in SA score for both groups. Such results raised questions as to the impact of cognitive decrements, relative to task difficulty and related effort whilst driving. It also provided evidence that Situation Awareness, rather than being uniformly good or bad, could, like any other psychological construct, be prone to change. These aspects were drawn together in a proposed model of driving SA.

The aging process is often accompanied by declines in one or more physical, vision, and/or cognitive abilities that may impact driving safety. As older drivers become more self-aware of these functional deficits, they have the tendency to engage in self-regulation practices, such as less driving and avoiding challenging driving situations. This tendency may gradually evolve to give up driving altogether. Advanced Driver Assistance Systems (ADAS) holds promise for improving older drivers' safety on the road as well as maintaining their mobility by compensating for declines in visual, cognitive, and physical capabilities. However, the perception of these technologies can influence the realization of these expected benefits. The overarching goal of this research is to understand and enhance the safety and mobility of older adults by examining the impact of ADAS. The dissertation addresses this goal by investigating mobility, perception, safety measures, and safety. Study 1 employed structure equation modeling (SEM) on the data from the Second Strategic Highway Research Program (SHRP 2) on driving habits with respect to age, gender, living status, health, and functioning capabilities. The results illustrate that older drivers' health is a reliable predictor of driving exposure, and cognitive and physical declines are predictive of their intention to reduce exposure and actual driving in challenging situations. These findings highlight that the aging population requires support for their mobility and likely road safety given their age-related impairments. Study 2 employed structure topic modeling on a focus group of older adults driving vehicles equipped with ADAS for six weeks was conducted to reveal five key issues to older drivers (in the order of prevalence): (1) safety, (2) confidence concerning ADAS, (3) ADAS functionality, (4) user interface/usability, and (5) non-ADAS related features. The findings point to a need for holistic ADAS design that not only must consider safety concerns but also user interfaces accommodating older adults' preferences and limitations as well as in-depth training programs to operate ADAS given the technology limitations. Study 3 employed correlation analysis and logistic regression on SHRP 2 data to reveal that the longitudinal deceleration events at greater than 0.60g and lateral acceleration events at greater than 0.40g appear most associated with older adults' driving risk and are predictive of near future crash and near-crashes (CNCs) occurrence and high-risk older drivers with acceptable accuracy. These findings indicate that high g-force events can be used to assess risk for older drivers, and the selection of thresholds should consider the characteristics of drivers. Study 4 compared high g-force events between two naturalistic driving studies to reveal that drivers who drove vehicles equipped with ADAS had lower longitudinal declaration rates, indicating the benefits of ADAS presence on older drivers' safety. When lane keeping assist (LKA) was engaged, lower high longitudinal deceleration was observed than when LKA was not engaged, indicating that older drivers tended to apply less aggressive braking when using LKA. Over several weeks of exposure to vehicles with ADAS presence, older drivers showed decreasing longitudinal deceleration but increasing lateral acceleration events. In other words, the potential of ADAS for positive safety-related impacts exists but some refinement in the design to reduce lateral events might be necessary. / Doctor of Philosophy / As people grow older, they may experience declines in their physical, vision, and cognitive abilities, which can affect their ability to drive safely. Many older drivers become more aware of these limitations and tend to drive less or avoid challenging situations, gradually some eventually stop driving altogether. Advanced Driver Assistance Systems (ADAS) hold the potential to enhance the safety and mobility of older drivers by compensating for these declines in vision, cognition, and physical capabilities. However, the way older adults perceive and accept these technologies can influence their effectiveness. This research focuses on understanding and improving the safety and mobility of older adults by examining the impact of ADAS on them through four studies. These studies fill gaps in research and provide insights into the potential of ADAS to enhance both the safety and mobility of older drivers. This research is vital for improving the quality of life for older adults and making our roads safer for all.

No description available.

Doctor of Philosophy / Department of Family Studies and Human Services / Karen Myers-Bowman / Due to health conditions, the average 70 year old will outlive the ability to drive by 6 years for men and 10 years for women (Foley et al., 2002). Driving loss has a significantly negative impact on the quality of life of an older adult. For this reason, some continue to drive despite concerns about safety. Midlife family members of older adults often feel social pressure to intervene in driving decision-making and social pressure to refrain from intervening. The goal of this study was to understand the experiences of midlife family members from the time that someone first noticed a concern with the older relative’s driving until the time the older adult stopped driving. A qualitative, multiple embedded case study approach was used to gather information from two midlife family members from 7 families with an older driver who had recently retired from driving. The family processes that influenced communication about driving and choice of strategies for intervening were examined. Findings indicated that the midlife family members became aware of safety issues at different times. Awareness prompted conversations with other relatives, and the majority of family conversations about driving did not include the older adult. Many family members reported a respect for the autonomy of the older relative and a reluctance to initiate conversations without permission from the older adult to do so. Intervention strategies reported by participants included (1) wait and worry, (2) nudging, (3) attempted conversation, (4) ending requests for driving assistance, (5) requesting assistance from physicians, (6) requesting assistance from the DMV, (7) requesting assistance from law enforcement, and (8) accepting the inability to end an older adult’s driving career. Participants reported many factors that both helped and hindered efforts to encourage driving retirement. Based on these findings, an Ecological Model of Later-Life Decision-Making was proposed. The model reflects that the participants’ efforts to encourage driving retirement were not simply a matter of intra-family communication, but were influenced by processes occurring at multiple levels, both within and outside of the family. Processes occurring at multiple levels both helped and hindered family members’ efforts to encourage driving retirement.

Master of Science / Department of Civil Engineering / Sunanda Dissanayake / Rapid increases are estimated in the percentage of elderly among the U.S. population starting in 2010. A majority of the older Americans depend on automobiles to meet their transportation needs either because of lack of public transportation or by choice. Ninety percent of total trips made by the elderly are by personal vehicle and seventy percent of this number involves the elderly driving the vehicles. However due to the aging process, older drivers experience a natural decline in sensory, cognitive, and other mental and physical capabilities as compared to younger drivers. This situation, combined with an imperfect highway infrastructure is making older drivers one of the most critical groups in terms of highway safety, thus demanding safer driving conditions. Safety concern for older drivers arises when the fatality rate per mile driven is considered, as exposure is one of the crucial factors contributing to increased fatality risk of older drivers. Hence, exposure reported in Billion Vehicle Miles Traveled (BVMT) was considered for this study. Crash data and exposure data were used to compute the fatality rates. Sources for this data are the Fatality Analysis Reporting System (FARS) and National Household Travel Survey (NHTS). A basic characteristics study was completed to compare the fatality risk of younger (16-24 yrs), middle-aged (25-64 yrs), and older drivers (65+ yrs). Crash details were screened to study the characteristics of older drivers involved in fatal crashes. Risk for older drivers due to other involved drivers of all ages divided into groups was studied to understand their distribution. A number of statistical methods like the chi-square test of independence, odds ratio and double paired comparison estimates were applied to study contributing factors of older driver’s increased fatal crash involvement. Results from the characteristics study for the elderly indicate that a majority of fatal crashes occur under daylight conditions with relatively higher seatbelt usage and non-alcoholic driving on straight level roads, which are generally considered as safer driving conditions. Other factors studied include vehicle-related variables like body type; manner of collision; roadway-related variables like roadway function class, month of the crash, and day of the week; and driver-related variables like race. Roadway functional class, vehicle body type, travel speed, number of drunk drivers, and the month in which the fatality occurred were found to have strong correlation with age of the older driver. Results from paired comparisons were used to estimate the fatality risk of older occupants as drivers and passengers under two different conditions considered simultaneously. Older drivers were found to have more fatality risk compared to older passengers. Recommended measures are also discussed to enhance older driver safety in the U.S.

There is a growing population of older people around the world and the population of older drivers is increasing in parallel. UK government figures in 2012 reported that there were more than 15 million people with a driving license aged over 60; more than 1 million of these were over 80. The aim of this thesis is to determine the requirements of older users for an improved driving experience leading to recommendations for the automotive industry. Initially it was necessary to understand some of the key issues concerning the driving experiences of older drivers; therefore a questionnaire survey of drivers of all ages (n=903) was conducted supplemented by interviews with drivers aged ≥ 65 years (n=15). Areas covered included: musculoskeletal symptoms, the vehicle seat, driving performance and driving behaviour. Respondents reported that they were dissatisfied with adjusting specific seat features, for example the head rest height and distance from the head; females reported more difficulty than males. Reaching and pulling the boot door down to close was difficult for 12% of older females. Older males and females also reported more difficulties with parallel parking and driving on a foggy day than younger drivers (p < 0.01). Nearly half of the sample (47%) reported that other drivers lights restrict their vision when driving at night. An in depth study was conducted to compare participants own vehicle (familiar) and a test vehicle (unfamiliar) to understand how design of the vehicle cab impacts on posture, comfort, health and wellbeing in older drivers (n=47, ≥ 50 years). The study involved functional performance assessments, seat set-up process evaluation (observations and postural analysis), ergonomics and emotional design based evaluations of car seat controls. Many issues were identified related to the seat controls such as operating, accessing, reaching and finding, particularly for the head rest height and lumbar support adjustments. Approximately 40% of the participants had difficulty turning their head and body around to adjust the head rest height, and the majority of these were over 80. This led to a series of workshops (including a participatory design exercise) with 18 participants (4 groups, ≥ 65 years).The aim was to explore the optimum positioning and operation of controls for older drivers. This research has provided foundational data and makes design recommendations for the automotive industry with a focus on making seat controls more inclusive (operation, location, type, size, colour and materials) and meet the requirements of older drivers.

Older adults are at an increased risk for motor-vehicle collisions (MVCs) once distance driven is considered, a finding that is partly attributed to a decline in attention related processes associated with age. MVCs typically occur in highly specific areas, suggesting a role of the complexity of the driving environment contributing to the occurrence of MVCs. The goal of this thesis was to explore the attentional demands of simulated driving events of varying complexity among young, mature and older drivers. In the present studies, attentional demand associated with driving was assessed through the peripheral detection task (PDT), a method in which a stimulus unrelated to the driving task is presented and drivers manually respond immediately upon its detection; latency to respond is recorded. The complexity of the driving environment was operationalized in terms of vehicle handling and of information processing elements. In the first study, inexperienced drivers completed a series simulated driving scenarios that varied according to their information processing and vehicle handling demands. The results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. Building on these findings, the second study employed the identical protocol as the first but examined differences in attentional demand between mid-aged and older drivers. The results indicated that when information processing demands were increased through the addition of traffic, and buildings, all participants exhibited greater workload regardless of age. The third study presented young, mid-aged, and older drivers with a simulated driving assessment course and administered several cognitive tasks. The results of the third study supported the hypothesis in that complex driving situations elicited greater attentional demand among drivers of all ages. Older adults showed greater attentional demand in comparison to young and mid-aged adults even after controlling for baseline response time. Older drivers also scored poorer on a global measure of driving safety. The results of this thesis highlight the roles of intrinsic and extrinsic factors involved in safe driving and are discussed in terms of appropriate interventions to improve road safety.

Older adults are at an increased risk for motor-vehicle collisions (MVCs) once distance driven is considered, a finding that is partly attributed to a decline in attention related processes associated with age. MVCs typically occur in highly specific areas, suggesting a role of the complexity of the driving environment contributing to the occurrence of MVCs. The goal of this thesis was to explore the attentional demands of simulated driving events of varying complexity among young, mature and older drivers. In the present studies, attentional demand associated with driving was assessed through the peripheral detection task (PDT), a method in which a stimulus unrelated to the driving task is presented and drivers manually respond immediately upon its detection; latency to respond is recorded. The complexity of the driving environment was operationalized in terms of vehicle handling and of information processing elements. In the first study, inexperienced drivers completed a series simulated driving scenarios that varied according to their information processing and vehicle handling demands. The results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. Building on these findings, the second study employed the identical protocol as the first but examined differences in attentional demand between mid-aged and older drivers. The results indicated that when information processing demands were increased through the addition of traffic, and buildings, all participants exhibited greater workload regardless of age. The third study presented young, mid-aged, and older drivers with a simulated driving assessment course and administered several cognitive tasks. The results of the third study supported the hypothesis in that complex driving situations elicited greater attentional demand among drivers of all ages. Older adults showed greater attentional demand in comparison to young and mid-aged adults even after controlling for baseline response time. Older drivers also scored poorer on a global measure of driving safety. The results of this thesis highlight the roles of intrinsic and extrinsic factors involved in safe driving and are discussed in terms of appropriate interventions to improve road safety.

Older adults are at an increased risk for motor-vehicle collisions (MVCs) once distance driven is considered, a finding that is partly attributed to a decline in attention related processes associated with age. MVCs typically occur in highly specific areas, suggesting a role of the complexity of the driving environment contributing to the occurrence of MVCs. The goal of this thesis was to explore the attentional demands of simulated driving events of varying complexity among young, mature and older drivers. In the present studies, attentional demand associated with driving was assessed through the peripheral detection task (PDT), a method in which a stimulus unrelated to the driving task is presented and drivers manually respond immediately upon its detection; latency to respond is recorded. The complexity of the driving environment was operationalized in terms of vehicle handling and of information processing elements. In the first study, inexperienced drivers completed a series simulated driving scenarios that varied according to their information processing and vehicle handling demands. The results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. Building on these findings, the second study employed the identical protocol as the first but examined differences in attentional demand between mid-aged and older drivers. The results indicated that when information processing demands were increased through the addition of traffic, and buildings, all participants exhibited greater workload regardless of age. The third study presented young, mid-aged, and older drivers with a simulated driving assessment course and administered several cognitive tasks. The results of the third study supported the hypothesis in that complex driving situations elicited greater attentional demand among drivers of all ages. Older adults showed greater attentional demand in comparison to young and mid-aged adults even after controlling for baseline response time. Older drivers also scored poorer on a global measure of driving safety. The results of this thesis highlight the roles of intrinsic and extrinsic factors involved in safe driving and are discussed in terms of appropriate interventions to improve road safety.

Older adults are at an increased risk for motor-vehicle collisions (MVCs) once distance driven is considered, a finding that is partly attributed to a decline in attention related processes associated with age. MVCs typically occur in highly specific areas, suggesting a role of the complexity of the driving environment contributing to the occurrence of MVCs. The goal of this thesis was to explore the attentional demands of simulated driving events of varying complexity among young, mature and older drivers. In the present studies, attentional demand associated with driving was assessed through the peripheral detection task (PDT), a method in which a stimulus unrelated to the driving task is presented and drivers manually respond immediately upon its detection; latency to respond is recorded. The complexity of the driving environment was operationalized in terms of vehicle handling and of information processing elements. In the first study, inexperienced drivers completed a series simulated driving scenarios that varied according to their information processing and vehicle handling demands. The results showed a reduction in PDT performance at intersections where information processing is increased as well as when handling maneuvers behind a lead vehicle were required. Building on these findings, the second study employed the identical protocol as the first but examined differences in attentional demand between mid-aged and older drivers. The results indicated that when information processing demands were increased through the addition of traffic, and buildings, all participants exhibited greater workload regardless of age. The third study presented young, mid-aged, and older drivers with a simulated driving assessment course and administered several cognitive tasks. The results of the third study supported the hypothesis in that complex driving situations elicited greater attentional demand among drivers of all ages. Older adults showed greater attentional demand in comparison to young and mid-aged adults even after controlling for baseline response time. Older drivers also scored poorer on a global measure of driving safety. The results of this thesis highlight the roles of intrinsic and extrinsic factors involved in safe driving and are discussed in terms of appropriate interventions to improve road safety.