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An ergonomic driver workspace and interface design is essential to ensure a healthier and comfortable driving experience in terms of driver perceptions, postures, and interface pressures. Developing more effective methods for driver-side interior design and evaluation, hence, requires thorough investigation of: 1) which perceptual responses are more relevant to ensuring ergonomic quality of a design, 2) the interrelationships among perceptual responses and objective measures, and 3) whether current assumptions regarding driver behaviors, and tools for specifying these behaviors, are valid for the design and evaluation. Existing studies, however, have rarely addressed these topics comprehensively, and often have been conducted with unsubstantiated assumptions. In contrast, this work sought to address these topics in a way that jointly considers characteristics of driver perceptions, behaviors, and objective measures to develop an improved design and evaluation methodology for driver workspace and interface, and that can also investigate the validity of implicit assumptions regarding perceptual relevance and drivers' behaviors. The first part of this work investigated drivers' perceptions in relation to driver workspace design and evaluation. Specifically, it examined the efficacy of several perceptual ratings, when used for evaluating automobile interface design. Results showed that comfort ratings were more effective at distinguishing among interface designs, in contrast to the current common practice of using discomfort ratings for designing and evaluating interface designs. Two distinct decision processes to relate local to global perceptions were also identified (i.e., global comfort as an average of local comforts, and global discomfort predominantly influenced by maximal local discomforts). These findings were observed consistently across age and cultural groups. In addition, this work provided empirical support for an earlier hypothetical comfort/discomfort model, which posited comfort and discomfort are complementary, yet independent entities. In order to facilitate the integration of driver perceptions and dynamic behaviors into driver workspace design and evaluation, the second part of this work clarified the relationships between perceptual ratings and various types of driver-seat interface pressure. Interface pressure was found to be more strongly related to overall and comfort ratings than to discomfort ratings, which is also in marked contrast with existing work that has focused on identifying association between discomfort and interface pressure. Specific pressure interface requirements for comfortable driver workspace design and evaluation were also provided. Lastly, this work specified more rigorous driving postures for digital human models (DHMs), based on actual drivers' perceptions, postural sensitivity, and static behavioral characteristics, to facilitate proactive design and evaluation that enables cost/time efficient vehicle development. Drivers' behavioral characteristics observed in this work were applied to the driver workspace design. First, postural sensitivity obtained by using a psychophysics concept has been applied to determination of core seat track ranges. Second, postural data have been used: 1) to review relevant industry standards on driver accommodation, 2) to investigate whether driving postures are bilaterally asymmetric, 3) to provide comfortable joint ranges, and lastly 4) to identify drivers' postural strategies for interacting with a vehicle. Overall, this work identified three important behavioral characteristics, specifically a bilateral imbalance in terms of interface pressure, bilaterally asymmetric joint posture, and postural strategies identified by cluster analysis. Such characteristics can be embedded in DHMs to describe more accurately actual driver behaviors inside a driver workspace, which is deemed to be a fundamental step to improved virtual ergonomic vehicle design and evaluation. In addition, the strategy-based classification method used in this work can be extended to simulate and predict more complex human motions. Practical and fundamental findings of this work will facilitate efficient and proactive design and evaluation of driver workspace and interface, and will help provide a healthier driving experience for a broader range of individuals. / Ph. D.

While safety-belt use markedly reduces morbidity and mortality, many young adults in the U.S. do not buckle-up 100% of the time. Following a series of community-level interventions on a university campus, this dissertation project focused on promoting individual-level safety-belt use. More specifically, a targeted web-based assessment and brief motivational intervention for individuals with lower rates of safety-belt use was developed and tested. A Pilot Study conducted prior to the Main Study developed self-reported assessment measures for safety-belt use and motivation. Recruitment, baseline assessment, intervention, and follow-up assessment were conducted via the Internet. Student drivers who buckled-up less than 70% of the time and who met other eligibility requirements were enrolled in a within subjects, randomized, attention-controlled design. At baseline, each participant completed an assessment of: (1) demographics; (2) driving behaviors; and (3) social cognitive and motivational variables including knowledge, perceived importance, confidence (self-efficacy), and readiness to buckle-up. Participants were then randomly assigned to one of two groups: (1) an attention-control group receiving emailed general nutrition information or (2) a motivational interviewing-consistent feedback group receiving emailed personalized feedback. Dependent variables were re-assessed approximately ten days after feedback/general nutrition information were emailed via follow-up assessment. Outcomes analyses using non-parametric statistics were conducted twice. First, an analysis of “completers” was conducted using data from those who completed follow-up. Second, a more conservative intent-to-treat analysis was conducted after carrying the last observation forward for those who did not complete follow-up, assuming no change among those who did not complete follow-up. Overall, results suggest this web-based assessment and brief motivational intervention was feasible and acceptable to participants. Overall, results from both analyses found statistically significant increases in median driver and passenger belt use between baseline and follow-up among participants in both groups. Further, effect sizes suggest the magnitude of change was greater among those in the intervention group versus those in the attention-control group. Participants were then categorized according to whether or not they increased driver belt use by at least one instance between baseline and follow-up. Those who received the intervention were not significantly more likely than those who received general nutrition information (i.e., assessment only) to increase driver safety-belt use by at least one instance. No statistical differences were found in either the completer or intent-to-treat analyses. Yet, when participants were categorized according to whether or not they increased passenger belt use by at least one instance between baseline and follow-up, those who received the intervention were 1.75 times more likely than those who received general nutrition information (i.e., assessment only) to increase passenger safety-belt use by at least one instance. This difference was not found in the intent-to-treat analysis. In general, study participation was associated with increased ratings of motivation (i.e., importance, confidence, and readiness) at follow-up. Results were interpreted with caution given psychometric weaknesses including high intercorrelations found between constructs of motivation in the Pilot Study. However, median change in one construct, readiness, was investigated in post-hoc analyses. Using the intent-to-treat sample, it was found that participants who were categorized as having increased driver safety-belt use by at least one instance also reported statistically significant median changes in readiness to buckle-up as a driver. Those categorized as having increased passenger safety-belt use by at least one instance also reported statistically significant median changes in readiness to buckle-up as a passenger. Further, although there was a trend for participants in the intervention group to be more likely than those in the attention-control group to commit to buckling-up and asking others to do the same at follow-up, there were no significant differences in commitment between groups. However, regardless of group assignment, change in median readiness was associated with: (1) commitment to buckle-up as a driver; (2) commitment to buckle-up as a passenger; (3) commitment to ask others to buckle-up while acting as a driver; and (4) commitment to ask others to buckle-up while acting as a passenger. Overall, these studies found the Internet to be an acceptable and promising venue for assessment and brief motivational intervention to promote safety-belt use among university students. Further, safety-belt use and motivational constructs such as importance, confidence, and readiness may be measured via self-report methodology. Results suggest participation in the study was associated with improvement in safety-belt use and some levels of motivation. While there were trends for those in the intervention group to report greater increases, there were no statistically significant differences between the groups in the ITT analyses. In the completer analyses, it was found that those in the intervention group were significantly more likely to report increased passenger safety-belt use. Future research may elucidate more specific psychometric properties of new measures used. In particular, readiness may be a proxy motivational variable that appears to relate to change in safety-belt use among drivers and passengers as well as commitment to buckle-up and ask others to do the same. The simple process of assessment may be sufficient to produce changes in readiness related to behavior change. / Ph. D.

The majority of car crash deaths occur in the front seats because the majority of occupants sit in the front seats. Traditionally, the rear seats were safer than the front seats because a front seated occupant would be closer to rigid structures such as the steering wheel, and they would be closer to the location of the impact. Therefore, government crash test regulations as well as academic and industry testing up to this point have principally focused on the front seats. Since the beginning of efforts to make cars safer, innovations were applied to the front seats first. Only some of these safety innovations have transitioned into the rear seats. Over the years, the front seats have gotten much safer due to advanced seatbelts with pretentioners and load limiters, airbags surrounding the driver, and structural changes to the vehicle frame to prevent intrusion into the occupant compartment. At the same time, occupant safety in the rear seats has also improved, however at only a fraction of the improvement of the front seats. With modern vehicles, the front seats have actually become safer than the rear seats for certain occupants and specific crash types (e.g., adult occupants in frontal crash). The lagging performance of the rear seats represents a problem because thousands of rear-seated occupants are injured or killed each year. With the rise in autonomous driving systems, the amount of occupants sitting in the rear seats, and therefore sustaining injury, could increase dramatically. In this dissertation, rear seats of a range of current vehicles were reconstructed to examine injury risk with the finite element models of two anthropomorphic test devices. These models showed a wide range of injury risks in the reconstructed seats. They were also able to show results similar to sled impact tests with the same vehicles. Knowledge gained from these reconstructions was then used to perform parametric studies on key variables that influence injury risk in the rear seats. From the parametric studies, it was found that the seat back angle, the width of the seatbelt anchors, and the presence of a seatbelt pretensioner had the largest influences on the injury risk. One of the injury mechanisms prevalent in the rear seats is submarining. Submarining likelihood and injury probability is difficult to predict with anthropomorphic test devices; however, human body models can help to improve injury prediction in these cases. To improve the injury prediction capability of human body models, several additions to the models are necessary. This dissertation outlines the investigation of spleen and kidney shapes through statistical shape analysis. This type of analysis allows more customizable human body models which could better capture the injury probability to these organs for a wider range of the population. Finally, subject-specific models of ribs were created to investigate factors affecting the predictive capability of finite element models. The findings and methodology from this body of work have the ability to add critical contributions to the understanding of injury risk and injury mechanisms in the rear seats. / Doctor of Philosophy / The majority of car crash deaths occur in the front seats because the majority of occupants sit in the front seats. Traditionally, the rear seats were safer than the front seats because a front seated occupant would be closer to hard objects such as the steering wheel, and they would be closer to the location of the impact. Therefore, government crash test regulations as well as academic and industry testing up to this point have principally focused on the front seats. Since the beginning of efforts to make cars safer, technology such as seatbelts and airbags were applied to the front seats first. Only some of this technology has been added into the rear seats. Over the years, the front seats have gotten much safer due to all the work focused on the front seats. At the same time, the rear seats have also improved, however at only a fraction of the improvement of the front seats. With modern vehicles, the front seats have actually become safer than the rear seats in some cases. The lagging performance of the rear seats represents a problem because thousands of rear-seated occupants are injured or killed each year. With the rise in self driving cars, the amount of occupants sitting in the rear seats, and therefore sustaining injury, could increase dramatically. In this dissertation, rear seats of a range of current vehicles were reconstructed to examine injury risk with the models of two crash test dummies. These models showed a wide range of injury risks in the reconstructed seats. They were also able to show results similar to physical tests with the same vehicles. Knowledge gained from this work was then used to help look at key variables that influence injury risk in the rear seats. It was found that the angle of the seat back, the width of the seatbelt anchors, and the presence of advanced seatbelts had the largest influences on the injury risk. One of the injury mechanisms prevalent in the rear seats is submarining, where the seatbelt slides up off the hips. Submarining likelihood and injury probability is difficult to predict with crash test dummies; however, human body models can help to improve injury prediction in these cases. To improve the injury prediction capability of human body models, several additions to the models are necessary. This dissertation outlines the investigation of spleen and kidney shapes to allow more customizable human body models which could better capture the injury probability to these organs for a wider range of the population. Finally, subject-specific models of ribs were created to investigate factors affecting the predictive capability of rib models. The findings and methodology from this body of work have the ability to add critical contributions to the understanding of injury risk and injury mechanisms in the rear seats.

Safety belt reminder systems are ubiquitously present in most, if not alI automobiles sold in the United States. Past research has found that the effectiveness of these reminder systems have shown minimal social benefit in the effort to increase safety belt use. The current investigation was conducted to determine if modified reminder systems could improve safety belt use. This research used an electronically equipped research vehicle sponsored by General Motors Corporation. The vehicle's research equipment allowed for the manipulation of different auditory reminder stimuli (i.e., chime, buzzer, and voice), temporal factors (e.g., presentation delays and second reminders) I and the measurement of the driver's safety belt use. Three modifications were explored: the presentation of a Delayed Reminder, Second Reminder, and comparisons of different auditory stimuli. The vehicle also permitted a single subject repeated measure design and methodology that provided process analysis. The results showed that the Delayed Reminder appeared ineffective at increasing belt use, whereas the Second Reminder was found to increase two out of nine subjects' safety belt response rates. The differential effects between the three auditory stimuli (i.e., Chime, Buzzer, & Voice) were inconclusive, though for two subjects the Buzzer and Voice were associated with safety belt increases. / Master of Science

This thesis presents the results of a research effort investigating the effect of belt usage reporting errors of National Automotive Sampling System-Crash Data System (NASS-CDS) investigators on injury risk estimates. Current estimates of injury risk are developed under the assumption that NASS-CDS investigators are always accurate at determining seat belt usage. The primary purpose of this research is to determine the accuracy of NASS-CDS investigators using event data recorders (EDRs) as the baseline for accuracy, and then recalculating injury risk estimates based on our findings. The analysis of a 107 EDR dataset, from vehicle tests conducted by the National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS), was conducted to determine the accuracy of Chrysler, Ford, GM and Toyota EDRs. This accuracy was examined by both EDR module type and vehicle make. EDR accuracy was determined for crash delta-V, seat belt buckle status, pre-impact speed, airbag deployment status and front seat position. From this analysis we were able to conclude that EDRs were accurate, within 4.5%, when comparing maximum delta-V of EDRs that recorded the entire crash pulse length. We also determined that EDRs were 100% accurate when reporting driver seat belt status for EDRs that completely recorded the event and recorded a status for the driver's seat belt. All GM, Ford and Chrysler EDRs in our database reported a pre-impact velocity less than 6 mph different than the NHTSA and IIHS reported pre-impact velocities. We also found that all but 2 (101 out of 103) of the GM, Ford, and Toyota EDRs correctly reported airbag deployment status. Lastly we were able to conclude that seat position status was useful in determining when a smaller sized occupant was the driver or right front occupant. EDRs reported seat position of 5% Hybrid III females as "forward" in every case that seat position was recorded for this smaller occupant size. Based on the analysis of seat belt status accuracy, a comparison of NASS-CDS investigator driver seat belt status and EDR driver seat belt status was conducted to determine the accuracy of the NASS-CDS investigators. This same comparison was conducted on reports of driver seat belt status provided by police. We found that NASS-CDS investigators had an overall error of 9.5% when determining driver seat belt status. When the EDR stated that the driver was unbuckled, investigators incorrectly coded buckled in of 29.5% of the cases. When the EDR stated that the driver was buckled, NASS-CDS error was only 1.2%. Police officers were less accurate than NASS-CDS investigators, with an overall error of 21.7%. When the EDR stated that the driver was buckled, police had an error of 2.4%. When the EDR stated that the driver's belt was unbuckled, police had an error of around 69%. In 2008, NASS-CDS investigators reported that drivers had an overall belt usage rate during accidents of 82%. After correcting for the errors we discovered, we estimate that the driver belt buckle status during a crash is around 72.6%. Injury risk estimates and odd ratio point estimates were then calculated for NASS-CDS investigator and EDR buckled versus unbuckled cases. The cases included only frontal collisions in which there was no rollover event or fire. Injury was defined as AIS 2+. The risk ratios and point estimates were then compared between investigators and EDRs. We found that injury risk for unbelted drivers may be over estimated by NASS-CDS investigators. The unbuckled to buckled risk ratio for EDRs was 8%-12% lower than the risk ratio calculated for NASS-CDS investigators. / Master of Science

Historically, rear seat occupants have been at a lower risk of serious injury and fatality in motor vehicle crashes than their front seat counterparts. However, many passive safety advancements that have occurred over the past few decades such as advanced airbag and seatbelt technology primarily benefit occupants of the front seat. Indeed, safety for front seat occupants has improved drastically in the 21st century, but has it improved so much that the front seat is now safer than the rear? Today, rear-seated occupants account for 10% of all passenger vehicle fatalities. In this era focused on achieving zero traffic deaths, the safety of rear-seated occupants must be further addressed. This dissertation analyzed U.S. national crash data to quantify the risk of injury and fatality to rear-seated passenger vehicle occupants while accounting for the influence of associated crash, vehicle, and occupant characteristics such as crash severity, vehicle model year, and occupant age/sex. In rear impacts, the risk of moderate-to-fatal injury was greater for rear-seated occupants than their front-seated counterparts. In high-severity rear impact crashes, catastrophic occupant compartment collapse can occur and carries with it a great fatality risk. In frontal impacts, there is evidence that the rear versus front seat relative risk of fatality has been increasing in vehicle model years 2007 and newer. Rear-seated occupants often sustained serious thoracic, abdomen, and/or head injuries that are generally related to seatbelt use. Seatbelt pretensioners and load limiters – commonplace technology in the front seating positions – aim to mitigate these types of injuries but are rarely provided as standard safety equipment in the rear seats of vehicles today. Finally, in side impacts, injury and fatality risks to rear- and front-seated occupants are more similar than in the other crash modes studied, though disparities in protection remain, especially in near-side vehicle-to-vehicle crashes. Finally, this work projects great injury reduction benefits if a rear seat belt reminder system were to be widely implemented in the U.S. vehicle fleet. This dissertation presents a comprehensive investigation of the factors that contribute to rear-seated occupant injury and/or fatality through retrospective studies on rear, front, and side impacts. The overall goal of this dissertation is to better quantify the current risk of injury to rear-seated occupants under a variety of crash conditions, compare this to the current risk to front-seated occupants, and, when possible, identify how exactly injuries are occurring and ways in which they may be prevented in the future. The findings can benefit automakers who seek to improve the effectiveness of rear seat safety systems as well as regulatory agencies seeking to improve was vehicle tests targeting rear seat passenger vehicle safety. / Doctor of Philosophy / Historically, if a passenger vehicle such as a sedan or SUV is in a crash, occupants who are rear-seated were less likely to be hurt than someone who was front-seated. In other words, rear-seated occupants have been at a lower risk of injury than front-seated occupants. Indeed, safety for front seat occupants has improved drastically in the 21st century due to advancements in airbag and seatbelt technologies, among others, but has it improved so much that the front seat is now safer than the rear? Today, of all vehicle occupants who are killed in crashes on U.S. roadways, 10% are rear-seated. During this time when conversations surrounding vehicle safety are focused on achieving zero traffic deaths, the safety of rear-seated occupants must be further studied. This dissertation looked at national databases of all police-reported crashes that occur each year in the United States. The risk of injury to rear-seated passenger vehicle occupants was quantified and compared to that of front-seated occupants. Factors that may increase or decrease this risk of injury and fatality such as crash type, vehicle type, and occupant demographics were further explored and reported. In vehicles that were rear-ended, the risk of injury was greater for rear-seated occupants than their front-seated counterparts. When a vehicle crashes into something front-first (the most common type of impact in a vehicle crash), evidence is presented that the risk of fatality is greater in the rear seats than the front seats in model year 2007 and newer vehicles which generally are equipped with the most recent airbag and seatbelt technology. When a vehicle is hit on either of its sides, the risk of injury is closer between rear- and front-seated occupants than it was in the rear-end or frontal crashes previously studied. That said, differences in occupant protection were still observed between the rear and front seats, especially when the occupants studied were seated on the closest side of impact, or the near-side, and the vehicle was struck by another vehicle rather than sliding into an object such as a pole. Finally, this work projects great injury reduction benefits if a rear seat belt reminder system were to be widely implemented in the U.S. vehicle fleet. This dissertation presents a comprehensive investigation of the factors that contribute to rear-seated occupant injury and/or fatality through retrospective studies on rear, front, and side impacts. The overall goal of this dissertation is to better quantify the current risk of injury to rear-seated occupants under a variety of crash conditions, compare this to the current risk to front-seated occupants, and, when possible, identify how exactly injuries are occurring and ways in which they may be prevented in the future. The findings can benefit automakers who seek to improve the effectiveness of rear seat safety systems as well as regulatory agencies seeking to improve was vehicle tests targeting rear seat passenger vehicle safety.

Recent research has demonstrated beneficial impact of incentives for safety belt promotion in a variety of environmental settings and has prompted the U.S. National Highway Traffic Safety Administration to promote and support community wide incentive programs for motivating safety belt use nationwide. Although influencing remarkable increases in safety belt use, these community efforts have definite weaknesses, including excessive costs, short-term intervention periods, limited evaluation data, and program delivery by outside agencies rather than indigenous personnel. This study reports the plan and outcome of a large-scale, safety belt program which overcame these disadvantages. The year-long ''Seatbelt Sweepstakes" began Fall 1983 in a large university community (21,000 students) and was delivered by the campus police. The 15 regular police officers recorded the license numbers of vehicles with drivers wearing a shoulder belt, and each Monday of quarterly intervention periods, ten raffle winners were drawn from these numbers. Winners received gift certificates donated by community merchants. A comprehensive evaluation scheme includes daily observations of shoulder belt use, periodic attitude surveys of program agents (police) and recipients (students), and continuous recording of program side-effects (e.g., number of parking tickets and speeding violations, safety belt use and injuries at accident scenes). For those drivers affiliated with the university (i.e., faculty, staff, and students) usage increased from a Fall baseline mean of 17% to 26% during the second incentive period, while usage for non-affiliated drivers increased to a lesser extent, from a pre-program mean of 16% to an incentive program mean of 1990. Winter withdrawal usage rates were 25% and 17%, respectively, suggesting that the program had a differential effect on university affiliated vs. non-university affiliated drivers. Faculty and staff had a higher Fall baseline usage percentage than students (19% vs. 15% mean usage for faculty/staff and students, respectively), increased their belt wearing as a result of the the intervention phases to a greater extent than students (33% vs. 20% mean usage for faculty/staff and students, respectively), and showed greater maintenance after the incentives were withdrawn in the Winter (30% vs. 22% mean usage for faculty/staff and students, respectively). A systematic evaluation of student opinions suggest that opinions toward campus police did not change significantly as a function of the Seatbelt Sweepstakes although an officer post program questionnaire indicated that the officers felt the students were responding in a more positive manner toward them specifically as a result of Sweepstakes 1 and 2. In addition to attitudinal measures, a cost effective analysis indicated that Sweepstakes 1 and 2 were relatively inexpensive to run and the implementation of the program interfered only slightly with officers' ongoing duties. / M.S.

Introdução - Para minimizar mortes e lesões entre crianças passageiras de automóveis existem os Assentos de Segurança Infantil (ASI), que são pouco utilizados ou utilizados erroneamente. Recente lei brasileira normatiza o uso de ASI e ressalta a necessidade de informações estatísticas, donde surgiu a intenção de estudar erros utilização de ASI com base em recente dissertação de mestrado que apontou uso de ASI por 36,1 por cento das crianças matriculadas em creches em Maringá. Não há dados brasileiros publicados quanto a erros de utilização de ASI. Objetivo - Analisar erros de utilização de ASI por crianças matriculadas usuários de creches em Maringá e fatores relacionados. Métodos - Estudo observacional transversal de coleta de dados prospectiva e eixo analítico retrospectivo. Resultados 42,7 por cento das crianças apresentavam erros de utilização. O modelo de regressão logística evidenciou maiores chances de erros na presença de duas ou mais crianças no veículo (OR = 5,10 com p = 0,007) e com menores níveis de escolaridade e renda dos pais (média renda e escolaridade OR = 7,00 com p = 0,003 e baixa renda e escolaridade OR = 3,40 com p = 0,03). Discussão Os dados são coerentes com publicações internacionais. Há expectativa dos efeitos da recente lei brasileira sobre uso de ASI, porém sabe-se que além da lei, há necessidade de estratégias educativas e facilitadoras de acesso aos ASI / Introduction - Minimize deaths and injuries among children who are passengers of vehicles with Child Safety Seat (CSS) which are not usually or wrongly used. A current Brazilian law regulates the use of CSS and enhances the need for information statistics, from which came the intention of studying errors in the use of CSS, based on a recent Master degree dissertation that pointed out that it is used in 36.1 per cent of the cases of children enrolled in day care centers in Maringá, Brazil. There is no data in Brazil published about the misuse of CSS. Objective - Analyze errors of CSS use by children who attend day care centers in Maringá and related factors. Methods - Observational and cross-sectional study of prospective data collection and retrospective and analytical axis. Results - 42.7 per cent of children demonstrated errors of use. The logistics regression model determined greater possibilities of errors in case of presence of two or more children in the vehicle (OR = 5.10, p = 0.007) and lower levels of parents´ education and income (average income and education OR = 7.00, p = 0.003 and low income and education OR = 3.40, p = 0.03). Discussion - The data is consistent to the international publications. There is an expectation about the effects of the current Brazilian law on the use of CSS, but it is known that besides the law, educational and facilitating strategies to the access to the CSS are necessary

Introdução - Para minimizar mortes e lesões entre crianças passageiras de automóveis existem os Assentos de Segurança Infantil (ASI), que são pouco utilizados ou utilizados erroneamente. Recente lei brasileira normatiza o uso de ASI e ressalta a necessidade de informações estatísticas, donde surgiu a intenção de estudar erros utilização de ASI com base em recente dissertação de mestrado que apontou uso de ASI por 36,1 por cento das crianças matriculadas em creches em Maringá. Não há dados brasileiros publicados quanto a erros de utilização de ASI. Objetivo - Analisar erros de utilização de ASI por crianças matriculadas usuários de creches em Maringá e fatores relacionados. Métodos - Estudo observacional transversal de coleta de dados prospectiva e eixo analítico retrospectivo. Resultados 42,7 por cento das crianças apresentavam erros de utilização. O modelo de regressão logística evidenciou maiores chances de erros na presença de duas ou mais crianças no veículo (OR = 5,10 com p = 0,007) e com menores níveis de escolaridade e renda dos pais (média renda e escolaridade OR = 7,00 com p = 0,003 e baixa renda e escolaridade OR = 3,40 com p = 0,03). Discussão Os dados são coerentes com publicações internacionais. Há expectativa dos efeitos da recente lei brasileira sobre uso de ASI, porém sabe-se que além da lei, há necessidade de estratégias educativas e facilitadoras de acesso aos ASI / Introduction - Minimize deaths and injuries among children who are passengers of vehicles with Child Safety Seat (CSS) which are not usually or wrongly used. A current Brazilian law regulates the use of CSS and enhances the need for information statistics, from which came the intention of studying errors in the use of CSS, based on a recent Master degree dissertation that pointed out that it is used in 36.1 per cent of the cases of children enrolled in day care centers in Maringá, Brazil. There is no data in Brazil published about the misuse of CSS. Objective - Analyze errors of CSS use by children who attend day care centers in Maringá and related factors. Methods - Observational and cross-sectional study of prospective data collection and retrospective and analytical axis. Results - 42.7 per cent of children demonstrated errors of use. The logistics regression model determined greater possibilities of errors in case of presence of two or more children in the vehicle (OR = 5.10, p = 0.007) and lower levels of parents´ education and income (average income and education OR = 7.00, p = 0.003 and low income and education OR = 3.40, p = 0.03). Discussion - The data is consistent to the international publications. There is an expectation about the effects of the current Brazilian law on the use of CSS, but it is known that besides the law, educational and facilitating strategies to the access to the CSS are necessary