Effectiveness Of Safety Belts Research Articles

Numerical analysis of passenger kinematics and injury risks during a railway vehicle collision: The effect of safety belts

The aim of this paper is to contribute to investigation of passive safety of passengers in railway vehicles using numerical simulations. At first, a typical interior of a railway vehicle is created in the Virtual Performance Solution software. It includes finite element models of seats. Their mechanical properties have been determined experimentally. Particular attention is paid to the table in the backseat as a potentially harmful element. In numerical simulations, both folded and unfolded states of the table are considered. The passenger is represented with the virtual human body model Virthuman. Its structure is composed of rigid bodies and deformable segments to account for deformability of soft tissues. It allows for the prediction of injury risk. The numerical simulations aim to investigate the potential benefit of standard seat belts in a railway vehicle. Therefore, the passenger is seated considering three configurations: seating with no constraints, belted with a two-point belt and a three-point belt. The interior is loaded with a crash-pulse prescribed by the GM/RT2100 regulation. The results are discussed in terms of passenger kinematics and injury risk.

What we do not know, hardly know, and really know about traffic safety

The July 1938 issue of the American Journal of Psychology contained an insightful paper on car driving(1). Since that time an enormous technical literature devoted to driving and traffic safety has emerged, resulting in a solid edifice of detailed knowledge(2). Yet many of the most basic questions remain unanswered according to the strictest scientific reasoning. For example, it is widely assumed that we know how a driver’s crash risk is affected by the consumption of alcohol(3). This has never been, nor ever can be, experimentally examined. Likewise, we have no direct experimental investigation of how a driver’s crash risk increases with increasing speed. Our estimate of the effectiveness of safety belts (4) in preventing fatalities rests on an assumption that we know is not true. The most reliable data we do have for most countries is a count of annual fatalities. Even though this is not quite perfect, changes from year to year are accurate provided any biases do not change much from year to year. An assumption-free dimensionless measure not subject to the above problems is a nation’s fatalities in a given year divided by that nation’s maximum number of fatalities in any year(5). Applying this measure to 2013 data from 26 countries leads to a crystal clear conclusion that is even more dramatic and irrefutable than that previously reported using earlier data.5 The USA is a stark outlier. From 1972 to 2013 traffic deaths in the USA declined by 40.1%. This was hailed as success by some USA policy leaders. However, in, for example, the Netherlands traffic deaths in the same period declined by 83.7%. If USA deaths had declined by the same percent as in the Netherlands, then in 2013 the USA would have suffered 8,87532,719 that actually occurred. If the USA had matched the declines recorded in any of 11 countries, then 20,000 fewer Americans would have been killed on the roads of the USA in 2013. The clear message is that the USA approach to safety (to be discussed) needs to change and should never be embraced by any other country.

Effect of Safety Belts on Chest Compression Quality in a Moving Ambulance

Objective This study aimed to examine the effect of specially designed safety belts on standard cardiopulmonary resuscitation (CPR) quality in a manikin and to determine whether straddle (STR) CPR is equivalent to standard CPR in a moving ambulance. Methods Thirty-five emergency medical technicians were recruited and divided into two groups. The first group subjects were randomly assigned to perform standard CPR with or without safety belts. The second group subjects wore safety belts and were randomly assigned to perform STR or standard CPR. Chest compression quality was evaluated by measuring the average rate, depth of compressions, the hands off time and incorrect hand position. Results The compression rate was significantly higher in the safety belt group (114.0/min vs. 106.5/min, p=0.001), but the compression depth was not significantly different. The hands-off time was also shorter in the safety belt group (24.5 seconds vs. 40 seconds, p=0.003). When STR CPR was performed, the compression depth was significantly deeper (42 mm vs. 36 mm, p=0.004), and the hands off time was shorter (6 seconds vs. 10 seconds, p=0.039) than with standard CPR. A follow-up questionnaire revealed that 65.7% of the respondents had stopped CPR in the past due to safety reasons, and 48.6% had been injured during CPR. Conclusions Wearing belts in a moving ambulance situation can increase the quality of CPR. If an appropriate belt can be designed, the STR method may be used effectively. (Hong Kong j.emerg.med. 2015;22:145-153)

Latent class analysis of the effects of age, gender, and alcohol consumption on driver-injury severities

This study explores the differences in driver-injury severity between drivers impaired and not-alcohol-impaired, while taking into consideration the role of age and gender. Using data from single-vehicle crashes from Illinois' Cook County over an eight-year period from January 1, 2004 to December 31, 2011, separate alcohol-impaired and not-alcohol-impaired models of driver-injury severity (with possible outcomes of no injury, minor injury, and severe injury) were estimated for younger male, older male, younger female, and older female drivers (those younger than 31 years old were considered younger drivers, and those 31 years old and older were considered older drivers). In addition to considering driver age, alcohol condition, and gender, a wide range of variables potentially affecting crash severity was considered, including a number of variables relating to highway attributes, vehicle characteristics, and environmental conditions. Using a latent class multinomial logit modeling approach to capture unobserved heterogeneity, estimation results show that there were substantial differences across age/gender groups in the absence/presence of alcohol. In addition, among others, particularly complex relationships were uncovered with regard to the impact of alcohol consumption, safety-belt effectiveness, roadway type, distracted driving, vehicle occupancy, and the effects of airbag deployment on injury severity.

Effectiveness of safety belts and Hierarchical Bayesian analysis of their relative use

Seat belts are effective devices for both preventing serious injury and reducing the likelihood of a fatality. Police crash data made available from the Emirate of Dubai in the United Arab Emirates are utilized to evaluate the effectiveness of safety seat belts and to propose a methodology to assess levels of the device use based on demographic factors. Analysis is based on rates and standardized rates. However, rates based on data disaggregated to small levels tend to be unreliable due extreme values resulting from small counts. A Hierarchical Bayesian approach is employed to smooth the standardized safety belt use rates (SBR). Extreme SBRs are shrunken towards an overall mean. Results of the analysis indicate that restrained occupants are less likely to incur fatal or serious injuries compared to the unrestrained. There is no significant difference between ethnic groups (local/expatriate) living in Dubai in terms of level of compliance with belt use.

Commentary: Supersized vans: A supersized problem

Commentary: Supersized vans: A supersized problem

Estimación del uso del cinturón de seguridad mediante un estudio de observación y una encuesta telefónica

To estimate the prevalence of safety-belt use in a telephone survey and an observational survey. Observational survey. Trained interviewers studied 4,067 front-seat occupants, at ten intersections of Madrid, according to "National Highway Traffic Safety Administration" guidelines. TELEPHONE SURVEY: We selected 433 front seat occupants from the Madrid city residential telephone directory. The questionnaire was completed by trained interviewers. Prevalence by the observational survey was 58.5%, and was significantly higher at interurban intersections (OR = 2.1) than city intersections. In the telephone survey, the overall prevalence was 94% at interurban area and 64% at city area and it was associated with no history of lines and positive opinion of effectiveness of safety belts. The safety belt prevalence observed is low, especially in the urban area. The telephone survey overestimates the safety belt use, but contributes with useful information for planning strategies.

Safety-belt effectiveness: The influence of crash severity and selective recruitment

While theoretical considerations show that the effectiveness of occupant protection devices declines from 100% at very low crash severity to 0% at high severity, empirical details have been lacking. When overall in-use effectiveness is estimated by applying traditional methods to data sets that lack a measure of severity, large biases are introduced because non-wearing drivers are riskier drivers, an effect that has been called selective recruitment. These effects are investigated empirically using National Accident Sampling System (NASS) data in which crash severity is measured by delta-v, the estimated change in the speed of the car as a result of the crash. Supplemental results are obtained using published police-reported data containing a more easily obtained but less objective severity measure. Both data sets provide information on driver fatalities and injuries, thus allowing four comparisons of effectiveness estimates based only on total casualties with ones taking into account the different severities of crashes by belted and unbelted drivers. The data show consistently that the probability that a driver is belted declines as crash severity increases. Belt effectiveness estimates ignoring this effect are biased upwards by large amounts (for example, 60% compared to 40% for injuries using NASS data). Belts appear more effective at preventing fatalities than at preventing injuries. The results are consistent with a prior estimate, derived using a method unaffected by the biases discussed here, which found that, averaged over all crashes, safety belts reduce driver fatality risk by (42 ± 4).

Light vehicle occupant ejections—A comprehensive investigation

Occupant ejections, about 1.5% of all crash-involved occupant events, are relatively infrequent but very harmful events in highway crashes of light vehicles, including cars, pickup trucks, vans, and multipurpose vehicles (utility vehicles, jeeps, etc.). The disparity between frequency of harm to ejectees and ejection frequency is at least one order of magnitude. Partial ejections, although less frequent, have an incidence that is comparable to that of complete ejections, except for restrained occupants, where complete ejections are very infrequent. Notwithstanding the high effectiveness of safety belts in preventing ejections, and the multifold growth of safety belt use in the last 10 years, there is no detectable reduction in the ejection rate in the same period. Ejections per se and not other pre-ejection occupant impacts are responsible for the bulk of the harm to ejectees. Furthermore, ejected occupants sustain harm much larger than that which would have occurred, had these occupants not been ejected. “Closed glazing” is the leading ejection path. “Doors” and “windshield” are distant seconds. All glazing except the windshield fail overwhelmingly by disintegration. Latch failure is the primary mode of failure in opening doors. Hinges and other modes of failure are relatively minor concerns. The sources of data in this investigation are: the National Accident Sampling System for the years 1988 to 1991, and the Fatal Accident Reporting System for 1982 to 1992.

Motorized two-point safety belt effectiveness in preventing fatalities

The effectiveness of two-point motorized restraint systems in preventing fatalities to outboard front-seat car occupants is estimated using published fatality data for one model car equipped with a motorized two-point-belt system, together with a number of assumptions. Ef- fectiveness estimates are obtained for the motorized belt system as used in the field, which reflects the mix of occupants who do and do not fasten the manual lap belt, and for effectiveness when the lap belt is not used. This latter estimate is, therefore, an estimate of the effectiveness of shoulder belts in preventing fatalities. In the data for the one car model, 18% of the fatally injured occupants were ejected. By assuming that three-point belt systems prevent ejection, these data are used to compute the difference in effectiveness between two-point and three- point systems. The result applies to the two-point belt system used in conjunction with whatever manual belt-use rates occurred in traffic. From published observations of lap-belt-use rates for this same vehicle, the effectiveness of the shoulder belt only is estimated. It is found that effectiveness of the two-point restraint system in conjunction with the lap-belt use that occurred in traffic is (32 ± 5)%. The effectiveness of the shoulder belt only is estimated as (29 ± 8)%.

Prospective study of the effect of safety belts in motor vehicle crashes

Trauma resulting from motor vehicle crashes (MVCs) is the leading cause of death in persons 1 to 38 years old. The following prospective study was undertaken to assess the effect of safety belts on the types of injuries sustained in MVCs. A total of 1,364 patients from four Chicago-area hospitals were evaluated prospectively during a six-month period. Safety belts reduced the incidence of head, facial, thoracic, abdominal, and extremity injuries sustained in MVCs. Spinal injuries comprised the only group in which safety belt wearers sustained injuries more frequently than safety belt nonwearers. Further research on the different safety belt designs and effects of air bags is needed to reduce the incidence of cervical and lumbar strain in restrained patients.

A quantification of the impact of restraining systems on passenger safety

Abstract Safety belt effectiveness was examined using accident data for the years 1984–1987 in the state of Alabama. Restraint effectiveness proportions were computed separately for rural and urban roads and different seating positions within the vehicle. These were pooled to obtain overall estimates of seatbelt effectiveness proportions for fatalities, which were (50.27 ± 1)% and 8% for front and back seat occupants, respectively. For serious injuries, the effectiveness proportions were estimated to be (48.72 ± 0.22)% for front seat and (57.34 ± 0.74)% for back seat occupants. A comprehensive comparison with existing studies was also performed, crystallizing the need for additional study on the motivating influence related to the wearing of seatbelts.

Prospective Study of the Effect of Safety Belts on Morbidity and Health Care Costs in Motor-Vehicle Accidents

To assess the impact of safety belt use on the extent of injuries sustained in motor-vehicle accidents and the incurred health care costs, 1364 patients were prospectively evaluated at four Chicago-area hospitals. Of these, 791 (58%) were wearing a safety belt whereas 573 (42%) were not. The mean injury severity score for safety belt wearers was 1.8 +/- 0.07 vs 4.51 +/- 0.31 in those not wearing a safety belt. Only 6.8% of safety belt wearers required admission vs 19.2% of those not wearing a safety belt. Restrained occupants incurred mean charges of $534 +/- $67 compared with $1583 +/- $201 in unrestrained occupants. Thus, safety belt wearers had a 60.1% reduction in severity of injury, a 64.6% decrease in hospital admissions, and a 66.3% decline in hospital charges. Our findings demonstrate the significant societal burden of nonuse of safety belts in terms of morbidity and the costs of medical care.

Prospective study of the effect of safety belts on morbidity and health care costs in motor-vehicle accidents

Comparaison de 791 sujets victimes d'accidents alors que leur ceinture etait bouclee et 573 qui n'avaient pas boucle leur ceinture. La gravite des lesions est moindre dans le 1er groupe (indice 1,8 contre 4,51); 6,8% des sujets du 1er groupe sont hospitalises, contre 19,2% du second. Le port de la ceinture permet une reduction importante du prix des traitements

Examination of some possible biases in double pair comparison estimates of safety belt effectiveness

Biases in double pair comparison estimates of safety belt effectiveness due to two effects (noncoding of some surviving passengers, and driver/passenger impact during crashes) are investigated by calculating effectiveness from fatality frequencies assumed altered by the biases. Noncoding surviving right-front passengers does not affect estimates for drivers, but does overestimate slightly passenger effectiveness. Two biasing driver/passenger contact effects occur for right-side impacts—a “cushioning” effect (risk to unbelted driver is reduced by striking passenger rather than the vehicle interior) and a “missile” effect (passenger risk is increased by being struck by unrestrained driver). Cushioning and missile effects both reduce estimates; their combined effects could cause right-side impact effectiveness to be underestimated by as much as 20% (probably much less). Correcting for all effects increases the overall estimate from 42.6% to 43.2%. Thus, to the nearest percent, the result is still that if all presently unbelted drivers and right-front-seat passengers were to become wearers, fatalities to this group would decline by (43 ± 3)%.

Safety belt effectiveness in preventing driver fatalities versus a number of vehicular, accident, roadway, and environmental factors

Safety belt effectiveness in preventing fatalities to drivers is examined versus a number factors (vehicle, accident, and environmental) by applying the double-pair comparison method to appropriate subsets of the Fatal Accident Reporting System (FARS) data. For each of 13 factors studied, safety belt effectiveness (the percent of fatally injured unbelted drivers who would not have been killed if they had been wearing safety belts) is estimated, as is an associated standard error of the estimate. The results, which are presented graphically, provide no evidence that safety belt effectiveness is systematically influenced by most of the factors investigated, including car mass and model year. The absence of any systematic relationship with car mass is in agreement with an earlier finding based on the pedestrian fatality exposure method; this agreement adds plausibility to the assumptions used for both the earlier and the present methods. Safety belt effectiveness is greater for single-car crashes (62 ± 5) % than for crashes involving two cars (30 ± 8) % , this difference being statistically significant at p<.02. The results suggest weakly that safety belt effectiveness is greater for two-door (48 ± 6) % than for four-door (38 ± 10) % cars, and is greater for striking (44 ± 6) % cars than for struck (27 ± 12)% cars. The above differences probably reflect higher effectiveness in frontal (or rollover) crashes than in side impacts.

The effectiveness of safety belts in preventing fatalities

The effectiveness of safety belts in preventing fatalities

Safety belt effectiveness in preventing driver fatalities versus a number of vehicular, accident, roadway and environmental factors : L. Evans and M.C. Frick, General Motors Research Laboratories, Warren, MI, October 1, 1985, GMR-5170

Safety belt effectiveness in preventing fatalities to drivers is examined versus 13 vehicle, accident or environmental factors by applying the double pair comparison method to appropriate subsets of the Fatal Accident Reporting System (FARS) data. For each factor safety belt effectiveness (the percent of fatally injured unbelted drivers who would not have been killed if they had been wearing belts) is estimated, as is an associated standard error of the estimate. The graphically presented results provide no evidence that safety belt effectiveness is systematically influenced by most of the factors investigated, including car mass and model year. The largest effect found was that safety belt effectiveness for single car crashes was (62 ±5)% compared to (30 ± 8)% for two-car crashes.

The effectiveness of safety belts in preventing fatalities

The effectiveness of safety belts in preventing fatalities to drivers and right front passengers is estimated by applying the double pair comparison method to 1974 or later model year cars coded in the Fatal Accident Reporting System. The method focuses on “subject” occupants (drivers or right front passengers) and “other” occupants (any except the subject occupant). Fatality risks to belted and unbelted subject occupants are compared using the other occupant to estimate exposure. In this study, drivers and right front passengers are subject occupants; choosing other occupants differing in age, seating positions, and belt use, generated 46 essentially independent estimates of safety belt effectiveness. The weighted average and standard error of these is (41 ± 4)%. This finding agrees with the 40%–50% range reported in a recent major review and synthesis by the National Highway Traffic Safety Administration. Combining this with the present determination gives (43 ± 3)%; that is, if all presently unbelted drivers and right front passengers were to use the provided three point lap/shoulder belt, but not otherwise change their behavior, fatalities to this group would decline by (43 ± 3)%.

The effectiveness of safety belts in preventing fatalities : L. Evans, General Motors Research Laboratories, Warren, MI, June 24, 1985, GMR-5088

The effectiveness of safety belts in preventing fatalities : L. Evans, General Motors Research Laboratories, Warren, MI, June 24, 1985, GMR-5088