The objective of this study was to characterize the risk of mild traumatic brain injury (MTBI) in living humans based on a large set of head impact data taken from American football players at the collegiate level. Real-time head accelerations were recorded from helmet-mounted accelerometers designed to stay in contact with the player's head. Over 27,000 head impacts were recorded, including four impacts resulting in MTBI. Parametric risk curves were developed by normalizing MTBI incidence data by head impact exposure data. An important finding of this research is that living humans, at least in the setting of collegiate football, sustain much more significant head impacts without apparent injury than previously thought. The following preliminary nominal injury assessment reference values associated with a 10% risk of MTBI are proposed: a peak linear head acceleration of 165 g, a HIC of 400, and a peak angular head acceleration of 9000 rad/s2.
Although most countries recommend transitioning children from rear facing (RF) to forward facing (FF) child restraints at one year of age, Swedish data suggests that RF restraints are more effective. The objective of this study was to compare RF and FF orientations in frontal sled tests. Four dummies (CRABI 12 mo, Q1.5, Hybrid III 3 yr, and Q3) were used to represent children from 1 to 3 years of age. Restraint systems tested included both 1) LATCH and 2) rigid ISOFIX with support leg designs. Rear facing restraints with support legs provided the best results for all injury measures, while RF restraints in general provided the lowest chest displacements and neck loads.
This study reports on an effort to evaluate and interrelate the existence and strength of two core laws and 14 expanded laws designed to (a) control the sales of alcohol, (b) prevent possession and consumption of alcohol, and (c) prevent alcohol impaired driving by youth aged 20 and younger. Our first analysis determined if the enactment of the possession and purchase laws (the two core minimum legal drinking age laws) was associated with a reduction in the ratio of drinking to nondrinking drivers aged 20 and younger who were involved in fatal crashes controlling for as many variables as possible. The ANOVA results suggest that in the presence of numerous covariates, the possession and purchase laws account for an 11.2% (p = 0.041) reduction in the ratio measure. Our second analysis determined whether the existence and strength of any of the 16 underage drinking laws was associated with a reduction in the percentage of drivers aged 20 and younger involved in fatal crashes who were drinking. In the regression analyses, making it illegal to use a false identification to purchase alcohol was significant. From state to state, a unit difference (increase) in the strength of the False ID Use law was associated with a 7.3% smaller outcome measure (p = 0.034).
Since nearly half of children fatally injured in automobile crashes were restrained, optimizing occupant protection systems for children is essential to reducing morbidity and mortality. Data from the Partners for Child Passenger Safety study were used to compare the differential injury risk between drivers and their child passengers in the same crash, with a focus on vehicle model year. A matched cohort design and conditional logistic regression model were used in the analyses. Overall, injury risk for drivers was higher than for children, but the risk difference was largest for the oldest model year vehicles, particularly for children aged 4-8 in seat belts. While drivers experienced significant benefits in safety with increasing model years, children restrained by safety belts alone derived less safety benefit from newer vehicles.
Based on real-world crash data and recent field studies, an ad-hoc group was set up in order to have a better comprehension of the effects of misuse of Child Restraint Systems (CRS) on child protection. A testing programme of 60 single misuse situations was conducted. Test results confirmed that, in frontal impact, children have higher risk of being injured on a number of different body regions when CRS's are misused. This work provides material for educational and training purposes to help parents understand that child restraints need to be correctly fitted in order to provide the level of protection they are designed for.
This study applies NASS/CDS, GES and FARS data to examine occupant exposure plus injury and fatality rates for belted occupants in frontal crashes by seating position, age and gender. The NASS data was used to examine the distributions by crash severity. The GES data showed that when two elderly occupants (age 65+) were present, the female occupied the right front passenger position 73% of the time. A paired comparison analysis using FARS data showed that, for elderly occupants (age 65+), the fatality risk for elderly right front passengers is 42% higher than for elderly drivers. The NASS/CDS analysis found 74% of the seriously injured vulnerable passengers with MAIS 3+ injuries were in crashes less severe than 26 mph. This group of injured occupants was made up of 43% aged 50 and older and 42% younger females. The injury rates for the older (age 50+) right front passengers were 1.8 times the rates for the elderly drivers. These results suggest the need for more benign safety systems for the right front passenger that are appropriate for the lower injury tolerance of the predominant occupants of that seating position.
Case-based hospital billing data from the Health Care Utilization Partnership was used to calculate annual statewide hospital charges for the acute care of traffic injuries in Nebraska. E-codes 810.0 through 819.9 identified traffic injury cases. Admissions and emergency department (ED)-only visits for traffic injuries accrued significantly higher charges than other types of care. Statewide, hospital charges for the acute care of traffic injury totaled more than U.S.dollars 63.8 million in 2004. Of this, 23.2% was charged to public payers (Medicare or Medicaid) and 5.5% was charged to self-pay (generally accepted as bad debt absorbed by the hospital system).
This paper reports the findings of a study of younger and older driver behaviour to hazardous traffic manoeuvres in a driving simulator. Hazardous situations on a highway and residential drive were studied and drivers' vision and vehicle performance responses were collected. While all drivers were able to avoid crashes, the finding that older drivers were consistently slower to fixate hazardous stimuli in the driving environment and were slower to respond presents a potentially serious road safety concern. Further research is warranted, especially under conditions of increasing traffic complexity.
This paper presents the potential safety benefits of the experimental French LAVIA Intelligent Speed Adaptation system, according to road network and system mode, based on observed driving speeds, distributions of crash severity and crash injury risk. Results are given for car frontal and side impacts that together, represent 80% of all serious and fatal injuries in France. Of the three system modes tested (advisory, driver select, mandatory), our results suggest that driver select would most significantly reduce serious injuries and death. We estimate this 100% utilization of cars equipped with this type of speed adaptation system would decrease injury rates by 6% to 16% over existing conditions depending on the type of crash (frontal or side) and road environment considered. Some limitations associated with the analysis are also identified. LAVIA is the acronym for Limiteur s'Adaptant à la VItesse Autorisée, a French Intelligent Speed Adaptation (ISA) project that was set up towards the end of 1999. At the time, 1998 French national road safety statistics recorded 8437 road related deaths, a figure which had shown virtually no positive evolution since 1994. Detailed analysis of the contributory factors involved in fatal road crashes highlighted the time-honoured crash and injury causation mechanisms - alcohol, speed and seatbelts. Of the three, excessive speed (over and above the posted speed limit) was a contributory factor in half of all fatal crashes Inappropriate behaviour such as excessive speeding can be dealt with either by legislative or driver-incentive programmes. The first of these two solutions involves the introduction of new legislation and/or the enforcement of existing laws. This is the domain of Public Authorities and will not be discussed in detail here. Alternatively, incentive schemes can involve the implementation of speed related driver assistance systems, categorised according to their voluntary or mandatory character and the degree of autonomy proposed to or imposed on the driver. The LAVIA project set out to address several possible combinations of these two factors. The generic term Intelligent Speed Adaptation (ISA) encompasses a wide range of different technologies aimed at improving road safety by reducing traffic speed and homogenising traffic flow, within the limit of posted speed limits. "Fixed speed limit" systems inform the vehicle of the posted speed limit whereas "variable speed limit" systems take into account certain locations on the road network where a speed below the posted limit is desirable, such as sharp curves, pedestrian crossings or crash black spots. Taken one step further, speed limit systems may also take into account weather and traffic flow conditions. These systems are known as "dynamic speed limit" systems and benefit from real time updates for a specific location. The different ISA systems are generally characterised by the degree of freedom of choice given to the driver in moderating his or her speed. Speed limit technologies may be advisory (informing drivers of the current speed limit and speed limit changes), voluntary (allowing the driver to decide whether or not to implement speed limitation) or mandatory (imposing the current speed limit). The information supplied may be provided by way of the road infrastructure (and associated equipment), may be acquired autonomously by the vehicle or may be based on an interaction between the infrastructure and the vehicle. Even the most basic of these systems should be considered as a very useful driver aid, helping the driver to stay within the posted speed limit, avoiding "unnecessary" speeding fines through inattention, modelling driver behaviour through the long term reduction of speeds and reducing driver workload by limiting visual speedometer controls. Vehicle-based ISA systems should not be confused with internal systems. These latter systems rely upon the driver entering the desired travel speed, which is then maintained by cruise control or set as a maximum value by automatic speed regulators. Although these systems will not be discussed in detail here, it should be noted that the engine management technologies that they employ are a vital component of ISA systems.
From December 2000 until July 2002 a package of speed-related initiatives and factors took place in Victoria, Australia. The broad aim of this study was to evaluate the overall impact of the package on crash outcomes. Monthly crash counts and injury severity proportions were assessed using Poisson and logistic regression models respectively. The model measured the overall effect of the package after adjusting as far as possible for non-speed road safety initiatives and socio-economic factors. The speed-related package was associated with statistically significant estimated reductions in casualty crashes and suggested reductions in injury severity with trends towards increased reductions over time. From December 2000 until July 2002, three new speed enforcement initiatives were implemented in Victoria, Australia. These initiatives were introduced in stages and involved the following key components: More covert operations of mobile speed cameras, including flash-less operations; 50% increase in speed camera operating hours; and lowering of cameras' speed detection threshold. In addition, during the period 2001 to 2002, the 50 km/h General Urban Speed Limit (GUSL) was introduced (January 2001), there was an increase in speed-related advertising including the "Wipe Off 5" campaign, media announcements were made related to the above enforcement initiatives and there was a speeding penalty restructure. The above elements combine to make up a package of speed-related initiatives and factors. The package represents a broad, long term program by Victorian government agencies to reduce speed based on three linked strategies: more intensive Police enforcement of speed limits to deter potential offenders, i.e. the three new speed enforcement initiatives just described - supported by higher penalties; a reduction in the speed limit on local streets throughout Victoria from 60 km/h to 50 km/h; and provision of information using the mass media (television, radio and billboard) to reinforce the benefits of reducing low level speeding - the central message of "Wipe Off 5". These strategies were implemented across the entire state of Victoria with the intention of covering as many road users as possible. This study aimed to evaluate the overall effectiveness of the speed-related package. The study objectives were: to document the increased speed camera activity in each speed limit zone and in Melbourne compared with the rest of Victoria; to evaluate the overall effect on crash outcomes of the package; to account as far as possible for the effect on crash outcomes of non-speed road safety initiatives and socio-economic factors, which would otherwise influence the speed-related package evaluation; and to examine speed trends in Melbourne and on Victorian rural highways, especially the proportions of vehicles travelling at excessive speeds. This paper presents the results of the evaluation of the overall impact on crash outcomes associated with the speed-related package, after adjusting as far as possible for the effect of non-speed road safety initiatives and socio-economic factors. D'Elia, Newstead and Cameron (2007) document the study results in full.
A survey of motor vehicle child restraint use found around 28% of children under the age of six using weight-inappropriate restraints. Many parents did not know when a child was likely to outgrow a booster seat nor the weight of their child, but they did know the child's age. Anthropometric data show that, if advice on restraint transition, given solely in terms of age (6 months, 4 years, 8 years) were followed in Australia, incorrect restraint selection would occur in 5% of children under the age of six. Further analysis suggests how rewriting the Standard could reduce this number. We present an argument for placing age-based transitions at the heart of the strategy to improve child restraint compliance. This may be superior to one based on the child's weight or other anthropometric measurement. Our argument may be summarized as follows: 1 Age-based rules for selecting child restraints are simple, require less information to be retained, and might be more natural criteria for parents. They might have a greater chance of being adopted as norms, and of encouraging good peer cues. Anthropometric rules, on the other hand, assume that parents know the current dimensions of their children and have the tools at their disposal to measure these dimensions. 2 The consequences of age-based promotion for the proportion of children in a restraint suitable for their weight can be estimated for alternative regulatory frameworks. We will report such Calculations below and show that this rate can potentially be very high. The rate would be even higher if child restraint design standards were drafted with age-based transitions in mind. Age-based transitions imply restraint specifications (weight and height limits) that can be determined from anthropometric survey data. 3 Such standards would necessarily imply overlapping anthropometric ranges for the different types of restraint. However, we emphasize that these overlaps would exist to facilitate age-based transitions, not to feature in publicity advising on the correct selection of child restraints. Under such a regime, promotion is driven by what information is readily usable by parents, and ceases being consequential to the standards-setting process. In support of this argument we shall report a survey of restraint use among parents of pre-school and school aged children, and an analysis of the weights (or other dimensions) of children that provides a technique for estimating how well age-based transition could work. The remainder of this paper is divided into sections covering the survey and the anthropometric study. These are synthesized in a discussion of their implications for restraint promotions and standards setting.
This study finds that the break-even point for child safety seat misuse reduction programs and vehicle and seat design improvements is dollars 121 a year per child seat in use, annual misuse reduction program cost is dollars 6, and Lower Anchors and Tethers for Children (LATCH) cost dollars 13 annually per seat in use (in 2004 dollars). To estimate societal injury cost savings we compared tow-away crash outcomes for children ages 0-4, traveling in child seats in the back of passenger vehicles in 1984-1986 vs. 1999-2005. Both injury frequency and severity were compared and entered into the calculation of mean injury costs. To analyze the economic benefits of child safety seat misuse reduction programs and vehicle and seat design improvements for children sitting in rear seats of passenger vehicles, we compared outcomes of tow-away crashes for children ages 0-4 traveling in a child safety seat in two different multi-year time periods: 1984-1986 and 1999-2005. We chose 1984-1986 as a baseline as those years featured large, high-quality samples of crash data during the time period before the ongoing misuse of child seats was recognized as a public policy problem. By the early 1990s, misuse was a policy issue and misuse reduction programs were springing up.
The US Federal Motor Vehicle Safety Standard for frontal protection requires vehicle crash tests into a rigid barrier with two belted dummies in the front seats. The standard was recently modified to require two separate 56 Kph frontal tests. In one test the dummies are 50% males. In the other test, the dummies are 5% females. Analysis of crash test data indicates that the 56 Kph test does not encourage technology to reduce chest injuries in lower severity crashes. Tests conducted by Transport Canada provide data from belted 5% female dummies in the front seats of vehicles that were subjected crashes into a rigid barrier at 40 Kph. An analysis of the results showed that for many vehicles, the risks of serious chest injuries were higher in the 40 Kph test than in a 56 Kph test. This paper examines the benefits that would result from a requirement for a low severity (40 Kph) frontal barrier crash test with two belted 5% female dummies and more stringent chest injury requirements. A preliminary benefits analysis for chest deflection allowable in the range of 28 mm. to 36 mm. was conducted. A standard that limits the chest deflection to 34 mm. would reduce serious chest injury by 16% to 24% for the belted population in frontal crashes.
We investigated whether the rating obtained in the EuroNCAP test procedures correlates with injury protection to vehicle occupants in real crashes using data in the UK Cooperative Crash Injury Study (CCIS) database from 1996 to 2005. Multivariate Poisson regression models were developed, using the Abbreviated Injury Scale (AIS) score by body region as the dependent variable and the EuroNCAP score for that particular body region, seat belt use, mass ratio and Equivalent Test Speed (ETS) as independent variables. Our models identified statistically significant relationships between injury severity and safety belt use, mass ratio and ETS. We could not identify any statistically significant relationships between the EuroNCAP body region scores and real injury outcome except for the protection to pelvis-femur-knee in frontal impacts where scoring "green" is significantly better than scoring "yellow" or "red".
Evaluations of crash protection safety features require measures for quantifying impact severity. Velocity change (delta-V) is the major descriptor of collision severity used in most real-world crash databases. One of the limitations of delta-V is that it does not account for the time over which the crash pulse occurs (delta-t). Late model GM vehicles equipped with event data recorders capture the cumulative delta-V in 10 ms intervals over the crash pulse. Deceleration can be readily calculated from these data and provides a complementary measure of severity that has not previously been available for real world crashes. The relationship between maximum delta-V and deceleration was examined for different vehicle platforms involved in real world frontal impacts and frontal crash tests. Maximum deceleration was observed to be closely correlated to the maximum delta-V.
In the United States in 2005, there were 1,189 fatal crashes and 35,000 injurious crashes into guardrails. Current efforts to reduce fatalities occurring in guardrail collisions have focused on frontal oblique collisions of cars and light trucks into guardrail. These crashes however represent a diminishing target population for fatality reduction. This paper examines the current opportunities for reducing fatalities in guardrail collisions in the United States. The analysis was based upon crash data from the Fatality Analysis Reporting System (FARS) and the National Automotive Sampling System General Estimates System (GES) for the years 2000-2005. The greatest opportunity for fatality reduction is the protection of motorcyclists, who now account for 32% of guardrail fatalities, and car and light truck occupants in side impact, who now comprise 14% of all guardrail fatalities. Together, protection of motorcycle riders and protection of car and light truck occupants in side impacts account for nearly half of all fatalities (46%) which occur in vehicle-guardrail collisions. Additional targets for fatality reduction include light truck rollover and collisions with guardrail ends.
Despite the significant increase in mortality among older motorcyclists during the past decade, few studies have addressed specific injuries or mortality rates among all those injured. The purpose of this study is to describe the crash and injury characteristics among a cohort of motorcyclists injured in Maryland, and to determine the influence of age and crash type on mortality, injury patterns, and place of death (scene vs. hospital). Possible biases introduced by studying only those hospitalized are described. Based on the findings, specific injury prevention strategies for older vs. younger riders are proposed.
This study identified casualty crash types for which teen drivers experience excess risk relative to adults. Michigan State Police crash records were used to examine casualty crashes in two statewide populations of drivers who experienced at least one crash from 1989-1996 (pre-graduated driver licensing in Michigan): teens (ages 16-19) and adults (ages 45-65). Rates and rate ratios (RR) based on crash occurrence per 100,000 person miles driven (PMD) compared teens and adults from the two statewide populations. Excess risk was defined as a RR for a specific type of crash that was significantly greater than the RR for all crashes combined. The RRs for all crashes combined for teenage males was 2.41 and 1.75 for teenage females. RRs for teenage males ranged from a low of 2.16 for casualty crashes attributed to alcohol to 8.98 for casualty road departure crashes at night. Among teenage females, RRs ranged from 2.06 for casualty crashes on the weekend to 7.86 for casualty crashes at night with passengers. Casualty crash rates for teenage males ranged from 0.21 per 100,000 PMD for rollover crashes to 1.95 per 100,000 PMD for crashes with passengers. Among teen females, casualty crash rates ranged from 0.21 per 100,000 PMD for drink/driving with passengers to 3.31 per 100,000 PMD for crashes with passengers. Implications for graduated driver licensing, teen driver supervision, and policy are discussed. This study was funded by the National Institute on Alcohol Abuse and Alcoholism and the Centers for Disease Control and Prevention's National Center for Injury Prevention and Control.
Side impact pole/tree crashes can have devastating consequences. A series of 53 CIREN cases of narrow-object side impacts were analyzed. Twenty-seven of 53 had serious chest injury and 27 had serious head injury. Unilateral chest trauma led to the examination of residual crush pattern that often demonstrated oblique door intrusion into the occupant thorax space. It was hypothesized that unilateral chest trauma was caused by antero-lateral chest loading. This hypothesis was evaluated by conducting two (PMHS and ES2) vehicle side impact tests into a rigid pole. The PMHS test produced an oblique chest deformation pattern with injuries very similar to the real world trauma: unilateral rib fractures, spleen laceration, pelvic fracture, and a basilar skull fracture. Narrow-object side impacts are severe crash environments that can induce oblique chest loading and unique head trauma. Because the human may be more vulnerable in this type of crash scenario, dummy response and measurements, as well as a re-examination of side injury criteria may be necessary to design appropriate injury-mitigating safety devices.
This study was initiated to quantify the effects of the misuse in LATCH lower webbing. In the short period since the implementation of the LATCH system several cases of potential misuses have been reported. A series of sled tests in frontal impact mode were conducted with various misuse conditions (loose attachment of LATCH lower webbing, misrouting of LATCH lower webbing and child seat back inclination) for both forward and rearward facing child safety seats (FFCSS and RFCSS). Results from these tests are compared and discussed with that of the standard test with no misuse and showed that as the slack in the lower LATCH webbing increased, ATD injury measures exceeded the limits. The FFCSS tests in the reclined condition yielded lower injury values for all except the chest G's when compared to the standard upright test. In the misrouting tests the ATD kinematics depended on the routing pivot point, the lower the pivot point the better the ATD kinematics. Similar findings were also observed in the RFCSS tests. The use of top tether with the FFCSS substantially improved the performance of the Hybrid III 3 year old ATD in spite of misuse conditions and the injury values were lower than the corresponding tests with no top tether. The effective reduction was 37% in the HIC values, 6% in the chest G's, 30% in the head excursion, 22 % in the knee excursion and finally 37 % reduction in the Nij values.
