CORRELATES OF SEAT BELT USE AMONG TURKISH FRONT SEAT OCCUPANTS SimSekoglu, &Ouml / zlem M.S., Department of Psychology Supervisor: Assoc. Prof. Dr. Timo Lajunen June, 2005, 79 pages This thesis included three separate studies, which were observational, interview and survey studies, on seat belt use among Turkish front seat occupants. The observation study investigated occupant characteristics and environmental factors affecting seat belt use. Seat belts were used significantly more among females and older occupants than among males and younger occupants / and on intercity roads, at weekends and in the afternoons than on city roads, at weekdays and in the evenings. The interview study investigated the common reasons for using and not using a seat belt in different trip types, qualitatively. Safety, situational conditions, habit and avoiding punishment were the commonly reported reasons for using a seat belt, while situational conditions, not believing the effectiveness of seat belt use, discomfort and no habit of using a seat belt were the commonly reported reasons for not using a seat belt, for most of the trip types. In the third study, seat belt use both on urban and rural roads were explained with the basic and extended Theory of Planned Behavior (TPB) models and Health Belief Model (HBM), using Structural Equation Modeling. Basic TPB model showed a good fit to the data, while extended TPB model and HBM showed a low fit to the data. Within TPB constructs, attitudes and the subjective norm had a positive and significant relation to intentions to use a seat belt. Results were discussed for their implications to traffic safety in Turkey, along with limitations of the study and suggestions for further studies.

Introduction: Several authors have demonstrated that, while cycling at a constant power output, EMG activity from the gastrocnemius increases systematically with increases in pedaling cadence, but that soleus EMG remains unchanged (Marsh & Martin 1995; Sanderson et al. 2006). The reason for this differential effect of cadence on the muscles of the triceps surae is unclear. Whatever factor(s) are responsible, it is assumed that, as they vary, the differential electromyographic response will vary accordingly. Decreasing the seat height has been shown to alter the kinematic characteristics of cycling (Too, 1990). The first objective of this study was to examine the effect of a decrease in seat height on the kinematics and muscle activation of the lower limb. The second objective was to investigate the effect of seat height on the relationship between cadence and triceps surae activation and, in doing so, to reveal possible factors mediating the response to changes in cadence. Methods: Participants pedaled a cycle ergometer at 200 Watts for five minutes at each of five cadences (50, 65, 80, 95, 110 rpm) and at each of two seat heights (100% and 90% trochanteric height). Kinematics of the lower limb were calculated from digitized video records of reflective markers placed on the skin over seven bony landmarks. EMG data were collected from eight lower-limb muscles. Results: The most notable findings were 1) that activation of the gastrocnemii was less in the low-seat condition and, contrary to what the findings of past research would suggest, was not associated with changes in muscle length; 2) that the medial and lateral gastrocnemii responded differently to changes in cadence at each seat height, suggesting that the functional roles of these muscles in cycling differ; 3) that several factors, including muscle length, muscle velocity, ankle angle and the direction of muscle action, were not responsible for the differential effect of cadence on activation of the soleus and gastrocnemius. Future research should investigate afferent feedback from proprioceptors in the knee joint and knee extensor muscles as possible factors mediating the effect.

This research is concerned with exploring the relationship between car driving and musculoskeletal troubles and following on from this investigating methods which could aid the automotive industry in the design and evaluation of car seats. The thesis is divided into two parts. Part I describes the development and results of an epidemiological survey undertaken with data obtained from two sample groups. Study 1 was an interview survey (based on the Nordic Questionnaire) of 600 members of the British public, randomly selected within the strata of age and gender. Study 2 used the same interview, but with two carefully chosen groups of police officers (n=200). The results indicated that car drivers (especially those who drove as part of their job) appeared to be at risk in terms of reported discomfort and sickness absence due to low back trouble. Evidence from this and other studies has also indicated that drivers with the most adjustable driving packages may benefit in terms of both reduced discomfort and reduced sickness absence. This provided the background for the subsequent research in Part II and some impetus for car manufacturers to consider health issues in the design of car workstations. Part II involved a series of three experiments designed to investigate methodologies which could be used by manufacturers to predict car seat discomfort The literature was reviewed to identify suitable predictive techniques which would be robust enough to provide information to the automotive industry in 'real world' situations. The technique of interface pressure measurement had already generated interest in some seat manufacturers and was therefore selected for investigation. As a result of the findings in experiment 1, established guidelines for a comfortable driving posture may need to be modified. The other two experiments were designed to create discomfort in subjects firstly by varying foam hardness and secondly by varying posture. A clear, simple and consistent relationship between interface pressure and discomfort in realistic driving situations was not identified. Future studies using this technique should provide information regarding such factors as gender, the body mass index, anthropometric data, posture and foam hardness due to the confounding nature of these variables.

This thesis presents experimental studies on the relationship between external surface pressure and the perceived discomfort in seated body areas, in particular those under the ischial tuberosity and the mid-thigh. It consists of three parts. Part one provides a comprehensive review of the existing knowledge concerning seated discomfort. The current assessment methods of seated discomfort are summarised, with the emphasis on the validity and reliability of the rating scale methods. The implications of surface pressure to seated people are outlined from the perspective of clinical, sensory and perceptual, and ergonomics domains. A brief review of current technologies for pressure measurement is also provided. Part two presents the experimental work. It starts with an exploratory assessment model of seated discomfort, based on pressure measures. Two preliminary experiments were conducted to test the feasibility of the model. Three further psychophysical experiments were carried out to test the validity and reliability of the selected six rating scales, and to investigate the effects of surface pressure levels on perceived pressure intensity and discomfort in the seated mid-thigh and ischial tuberosity areas. Surface pressure stimuli were applied to a seated body area of 3,318 mm2• Subjects judged three items of sensations: pressure intensity, local discomfort, and the overall discomfort. The main results are: I) A 50-point category partitioning scale was identified to be most sensitive and reliable for scaling pressure intensity and discomfort; 2) Sensations of pressure intensity and discomfort linearly increase with the logarithm of the pressure stimulus level; 3) Thresholds for pressure intensity and discomfort in the seated ischium and thigh areas were derived; 4) The sensitivity of intensity and discomfort to the stimuli differs between the locations .The mid-thigh is more sensitive to surface pressure than the ischium. It is considered that this is due to differences in load adaptation, body tissue composition and deformation; 5) Local pressure discomfort dominates the overall discomfort, and ratings of the local discomfort are higher than those of overall discomfort. Part three discusses the findings from this research. Four integration models of the overall discomfort from local discomfort components were proposed. The Weighted Average model asserts that the overall discomfort is a linear combination of local discomfort components, and that the weight of each local discomfort is the proportion of this component out of the arithmetic sum of all local discomfort components. The mechanisms of discomfort were analysed. The fundamental research presented herein uniquely contributes to the knowledge on the human perception of seated pressure discomfort. Although this is not application based, the findings contribute to the methods of seating comfort evaluation as well as provide criteria by which seat designers may formulate design requirements.

Introduction: Several authors have demonstrated that, while cycling at a constant power output, EMG activity from the gastrocnemius increases systematically with increases in pedaling cadence, but that soleus EMG remains unchanged (Marsh & Martin 1995; Sanderson et al. 2006). The reason for this differential effect of cadence on the muscles of the triceps surae is unclear. Whatever factor(s) are responsible, it is assumed that, as they vary, the differential electromyographic response will vary accordingly. Decreasing the seat height has been shown to alter the kinematic characteristics of cycling (Too, 1990). The first objective of this study was to examine the effect of a decrease in seat height on the kinematics and muscle activation of the lower limb. The second objective was to investigate the effect of seat height on the relationship between cadence and triceps surae activation and, in doing so, to reveal possible factors mediating the response to changes in cadence. Methods: Participants pedaled a cycle ergometer at 200 Watts for five minutes at each of five cadences (50, 65, 80, 95, 110 rpm) and at each of two seat heights (100% and 90% trochanteric height). Kinematics of the lower limb were calculated from digitized video records of reflective markers placed on the skin over seven bony landmarks. EMG data were collected from eight lower-limb muscles. Results: The most notable findings were 1) that activation of the gastrocnemii was less in the low-seat condition and, contrary to what the findings of past research would suggest, was not associated with changes in muscle length; 2) that the medial and lateral gastrocnemii responded differently to changes in cadence at each seat height, suggesting that the functional roles of these muscles in cycling differ; 3) that several factors, including muscle length, muscle velocity, ankle angle and the direction of muscle action, were not responsible for the differential effect of cadence on activation of the soleus and gastrocnemius. Future research should investigate afferent feedback from proprioceptors in the knee joint and knee extensor muscles as possible factors mediating the effect. / Education, Faculty of / Kinesiology, School of / Graduate

The study of cycling biomechanics typically requires measurement of pedal loads through force transducer instrumentation. However, analysis of seated cycling often necessitates the additional measurement of the loads exerted on the rider by the seat and handlebars. A stationary exercise bicycle was instrumented with two commercial six-axis force transducers at both the seat and handlebar locations via a custom designed mounting system. The system was tested by applying known forces and moments to the fixtures and proved capable of accurately measuring the loads. Additional data collected from cycling tests were compared to values from the literature to add supporting evidence to the validity of the system. The instrumented stationary bicycle was further used to study the accuracy of modeling seated cycling in OpenSim. Five participants cycled at a moderate resistance level for three trials. Force and moment data were collected by seat, handlebar, and pedal load cells, while kinematic data were collected by an optical motion capture system. Participant data were analyzed with the OpenSim residual reduction algorithm (RRA) tool excluding seat and handlebar loads. The RRA pelvic residual was then compared to an experimentally determined handlebar and seat equivalent (HBSE) calculated from respective load cell data. Graphical comparisons of the RRA and HBSE results showed strong correlations in Anterior-Posterior (A-P) and Superior-Inferior (S-I) force directions and to a lesser degree, Medial-Lateral (M-L) force and S-I moment directions. M-L and A-P moment plots showed the least correlation between RRA and HBSE. Statistical comparisons showed RRA errors likely within 5.2% body weight (BW) for forces and 2.4% BW*height for moments. Considering the average participant height and weight of 167.7 cm and 63.6 kg, respectively, recommended error ranges for RRA are roughly ±4.0% BW for forces and ±7.2% BW*height for moments. This indicates that the OpenSim RRA tool can be used for cycling analysis.

I dagens samhälle är det svårt att ta med befintliga bälteskuddar vid resa då de är mycket otympliga. Vid resa med bil som färdmedel krävs en särskild skyddsanordning för barn enligt lag. Syftet med arbetet är att underlätta för barnfamiljer att ut och resa med sina barn och samtidigt inte riskera säkerheten. Målet med arbetet är att ta fram ett koncept för en uppblåsbar bälteskudde som visualiseras med hjälp av en CAD-modell. Modellen visualiseras i ett uppblåst tillstånd och anpassas till barn som är mellan åldrarna 5-10 år. Vid hållfasthetsberäkningar avgränsas arbetet från att ta hänsyn till kuddens materialdata och analysera spänningskoncentrationerna som uppstår. Genom att samla in kundbehov med hjälp av intervjuer och analys av befintlig produkt, har en produktspecifikation upprättas som sedan är grunden till en konceptgenerering. Konceptgenereringen utförs både internt i form av en workshop och externt genom benchmarking. Med hjälp av systematisk utforskning och konceptpoängsättning struktureras och elimineras lösningsförslag för att slutligen erhålla det mest lämpliga konceptet. Det utvalda konceptet består av en stabil rektangulär kudde med remmar som fästmekanism för bältet. Kudden blåses upp med hjälp av lungkraft och förpackas i en extern påse. Konceptet anses uppfylla syftet då modellen ger en låg förpackningsvolym och samtidigt anses vara säker. För att garantera säkerheten krävs ytterligare hållfasthetsberäkningar och ett säkerhetstest utifrån den europeiska standarden. / As a parent of children these days, it is problematic to bring the booster seat with you due to inconvenience because of the generic shaping of the seats. Our intention with the study is to make it easier for parents to bring their kids when travelling without challenging their kids' safety. Our objective is to develop a concept of an inflatable booster seat by illustrating a CAD-model in inflated condition. The booster seat is appropriate for children of an age between 5 and 10 years. When calculating the strength, the study is limited to consider the material data of the seat and only analyzing the stress concentrations that occurs. By gathering customer needs, a product specification has been established, which there after has been utilised as the foundation for the concept generation. The concept generation was made internally in the form of a workshop and externally through benchmarking. By performing systematic research as well as a concept scoring, solutions were gathered and the most appropriate concept were found. The chosen concept consists of a stable rectangular booster seat with straps as a mounting mechanism for the seatbelt. The booster seat are inflated via pulmonary force and can be stored in an extern pouch. The concept is considered to fulfill its purpose due to its small volume when stored while still being considered as safe. To ensure safety levels and meet European standards, further strength calculations and safety-tests are necessary.

Data on safety belt use were collected at two swimming pools over three consecutive summers. The impact of several variables upon safety belt use was examined. First, an Intervention Program (IP) was designed, comprised of Promotional, Reward, and Feedback components. Second, an Awareness/Education (AE) strategy was introduced to children enrolled in swim lessons. Third, belt use was examined before and after a mandatory safety belt use law (BUL) was enacted in Virginia. The moderating effects of the BUL were studied by implementing both the IP and the AE interventions during the pre- and post-BUL environments. Finally, some aspects of a behavioral prompt (i.e., a "Personal" vs. an "Impersonal" delivery method), and their relationship to safety belt use were examined. Major findings include, those individuals most influenced by the IP in the pre-BUL environment were those same individuals who were influenced by the BUL. Thus, while the IF did have an impact upon mean safety belt use levels in the post-BUL context, belt use increases over Baseline were not as dramatic as those observed in the pre-BUL environment. / Master of Science

This study conducted a series of road tests in the regular fleet operations of a revenue service to better understand the relationship between vehicle seat design and driver fatigue, improve two newly proposed objective methods for evaluating driver fatigue, and provide design guidelines for evaluating and improving vehicle seat characteristics in terms of driver fatigue. Each driver completed a test session on two seat cushions - one a polyurethane foam cushion and one an air-inflated cushion. Objective measurements of pressure distribution were taken throughout each test session, while subjective measurements were collected using surveys taken at one-hour intervals. Based on these results, we find that the air-inflated seat cushion has advantages in terms of subjective measures of comfort, support, and fatigue. We show that the objective measure aPcrms highlights characteristic differences between seat cushions, as the air-inflated seat cushion provides less area in high pressure regions, thus occluding less blood flow to tissue in the seated area. While we were unable to effectively assess the validity of the proposed measures or improve them further, the characteristic difference between seat cushions is not highlighted by using previously existing objective measures. This implies that aPcrms is a more useful measure and should be considered when evaluating the subjective quality of seat cushion designs under dynamic conditions, such as those existing in commercial truck driving. / Master of Science

Tidigare forskning indikerar att psykologisk påverkan är effektivt i avsikt att öka bältesanvändningsfrekvensen inom kollektivtrafik (Young, m.fl., 2008). Studiens hypotes är att busschaufförer kan påverka passagerare psykologiskt till att använda säkerhetsbälten vid färd med kollektiv busstrafik med hjälp av uppmaningar. Frågeställningarna involverar huruvida busschaufförer kan påverka med en neutral, påtryckande och/eller humoristisk uppmaning samt hur bältesanvändningen ser ut inom olika åldersgrupper, om det är skillnad mellan kvinnors respektive mäns bältesanvändning och om människors vana påverkar bältesanvändningen. Fyra undersökningsgrupper användes för att testa de olika uppmaningsformerna, varav en av dessa var kontrollgrupp. Deltagarna var resenärer mellan städerna Lidköping och Skövde. Det var 93 passagerare som observerades och 40 av dessa intervjuades. Observationer av bältesanvändningen utfördes innan och efter utdelad uppmaning. Intervjuer rörande passagerares bältesanvändning utfördes efter utdelad uppmaning. Resultaten från observationerna visade inte på någon signifikant skillnad i bältesanvändningen efter utdelad uppmaning. Likaså fanns det ingen signifikant skillnad mellan kvinnors respektive mäns användning av säkerhetsbälte eller mellan passagerares aktuella bältesanvändning och vanan att använda säkerhetsbälte. Resultaten från intervjuerna visade på signifikanta skillnader mellan olika åldersgruppers bältesanvändning. Vid intervjuerna framkom det att uppmaningar troligen skulle öka bältesanvändningen bland passagerare, även om undersökningens resultat från observationerna inte var signifikanta. Det framgick även att bältesanvändningen troligen skulle öka om säkerhetsbältena var bekvämare och mer flexibla. Undersökningen indikerade att bältesanvändningen bland unga passagerare var lägre än bältesanvändningen bland medelålders passagerare och fokus bör därmed troligen läggas på att få de yngre passagerarna att använda säkerhetsbälte mer vid färd med kollektiv busstrafik. / Previous research indicates that it is possible to psychologically affect people to increase their seat belt use on public transport (Young, et al., 2008). The study's hypothesis is that bus drivers can affect passengers' psychologically to use seat belts on public transport by delivering requests. The research questions are whether drivers can affect passengers with a neutral, pressuring, and/or humoristic request, how the seat belt usage appears within different age groups, if there is a difference between the sexes in seat belt usage, and if passengers' habits influence their seat belt usage. Four experimental groups were observed, one of which was the control group. The participants were passengers on a bus traveling from Lidköping to Skövde. 40 participants of the 93 observed were interviewed. Observations of the participants' seat belt use were conducted before and after the delivered request. The results of the observations showed no significant difference in seat belt use after the given request. Neither was there a significant difference in seat belt use between the sexes or a difference between the passengers' seat belt use at the time of the interviews and their habits of using the seat belt on public transport. The results of the interviews showed a significant difference between age groups in seatbelt use. It was suggested that requests from the bus driver would increase the seat belt use, although the observational results were not significant. Furthermore if the seat belts were more comfortable and flexible the seat belt use might increase. Young adults use seat belts less than middle aged adults; therefore, focus should possibly be on increasing the seat belt use of young adults.