Unintentional injury deaths in children and youth, 2010–2019

Background: Unintentional injuries are the leading cause of death for children and youth aged 1–19 in the United States. The purpose of this report is to describe how unintentional injury death rates among children and youth aged 0–19 years have changed during 2010–2019. Method: CDC analyzed 2010–2019 data from the National Vital Statistics System (NVSS) to determine two-year average annual number and rate of unintentional injury deaths for children and youth aged 0–19 years by sex, age group, race/ethnicity, mechanism, county urbanization level, and state. Results: From 2010–2011 to 2018–2019, unintentional injury death rates decreased 11% overall—representing over 1,100 fewer annual deaths. However, rates increased among some groups—including an increase in deaths due to suffocation among infants (20%) and increases in motor-vehicle traffic deaths among Black children (9%) and poisoning deaths among Black (37%) and Hispanic (50%) children. In 2018–2019, rates were higher for males than females (11.3 vs. 6.6 per 100,000 population), children aged < 1 and 15–19 years (31.9 and 16.8 per 100,000) than other age groups, among American Indian or Alaska Native (AIAN) and Blacks than Whites (19.4 and 12.4 vs. 9.0 per 100,000), motor-vehicle traffic (MVT) than other causes of injury (4.0 per 100,000), and rates increased as rurality increased (6.8 most urban [large central metro] vs. 17.8 most rural [non-core/non-metro] per 100,000). From 2010–2011 to 2018–2019, 49 states plus DC had stable or decreasing unintentional injury death rates; death rates increased only in California (8%)—driven by poisoning deaths. Conclusion and Practical Application: While the overall injury death rates improved, certain subgroups and their caregivers can benefit from focused prevention strategies, including infants and Black, Hispanic, and AIAN children. Focusing effective strategies to reduce suffocation, MVT, and poisoning deaths among those at disproportionate risk could further reduce unintentional injury deaths among children and youth in the next decade.     

Characteristics of crashes and injuries among 14 and 15 year old drivers,by rurality

Purpose: Motor-vehicle crashes continue to be the leading cause of death for teenagers in the United States. The United States has some of the youngest legal driving ages worldwide. The objective of this study was to determine rates and factors associated with injury crashes among 14- and 15-year-old drivers and how these varied by rurality. Methods: Data for this cross-sectional study of 14- and 15-year-old drivers were obtained from the Iowa Department of Transportation from 2001 to 2013. Crash and injury crash rates were calculated by rurality. The relationship between crash and driver factors and injury was assessed using logistic regression. Findings: Teen drivers, aged 14 and 15 years, had a statewide crash rate of 8 per 1,000 drivers from 2001 to 2013. The majority of crashes occurred in urban areas (51%), followed by in town (29%), remote rural areas (13%), and suburban areas (7%). Crash and injury crash rates increased as level of rurality increased. The odds of an injury crash increased more than 10-fold with the presence of multiple other teens as passengers, compared to no passengers (OR = 10.7, 95% CI: 7.1–16.2). Conclusions: Although 14- and 15-year-old drivers in Iowa have either limited unsupervised (school permits) or supervised only driving restrictions, they are overrepresented in terms of crashes and injury crashes. Rural roads and multiple teen passengers are particularly problematic in terms of injury outcomes. Practical applications: Results from this study support passenger restrictions and teen driving interventions designed with a rural focus.     

Effect of Aging on Brain Injury Prediction in Rotational Head Trauma—A Parameter Study with a Rat Finite Element Model

Objective: The aim of this study was to investigate the possible effects of age-related intracranial changes on the potential outcome of diffuse axonal injuries and acute subdural hematoma under rotational head loading.

Methods: A simulation-based parametric study was conducted using an updated and validated finite element model of a rat head. The validation included a comparison of predicted brain cortex sliding with respect to the skull. Further, model material properties were modified to account for aging; predicted tissue strains were compared with experimental data in which groups of rats in 2 different lifecycle stages, young adult and mature adult, were subjected to rotational trauma. For the parameter study, 2 age-dependent factors—brain volume and region-specific brain material properties—were implemented into the model. The models young adult and old age were subjected to several injurious and subinjurious sagittal plane rotational acceleration levels.

Results: Sequential analysis of the simulated trauma progression indicates that an increase in acute subdural hematoma injury risk indicator occurs at an early stage of the trauma, whereas an increase in diffuse axonal injury risk indicators occurs at a later stage. Tissue stiffening from young adult to mature adult rats produced an increase in strain-based thresholds accompanied by a wider spread of strain distribution toward the rear part of the brain, consistent with rotational trauma experiments with young adult and mature adult rats. Young adult to old age brain tissue softening and brain atrophy resulted in an increase in diffuse axonal injuries and acute subdural hematoma injury risk indicators, respectively.

Conclusions: The findings presented in this study suggest that age-specific injury thresholds should be developed to enable the development of superior restraint systems for the elderly. The findings also motivate other further studies on age-dependency of head trauma.     

Values-in-action that support safe production

Introduction: Safe production is a sustainable approach to managing an organization’s operations that considers the interests of both management and workers as salient stakeholders in a productive and safe workplace. A supportive culture enacts values versus only espousing them. These values-in-action are beliefs shared by both management and workers that align what should happen in performing organizational routines to be safe and be productive with what actually is done. However, the operations and safety management literature provides little guidance on which values-in-action are most important to safe production and how they work together to create a supportive culture. Method: The researchers conducted exploratory case studies in 10 manufacturing plants of 9 firms. The researchers compared plant managers’ top-down perspectives on safety in the performance of work and workers’ bottom-up experiences of the safety climate and their rates of injury on the job. Each case study used data collected from interviewing multiple managers, the administration of a climate survey to workers and the examination of the plant’s injury rates over time as reported to its third party health and safety insurer. Results: The researchers found that plants with four values-in-action —a commitment to safety, discipline, prevention and participation—were capable of safe production, while plants without those values were neither safe nor productive. Where culture and climate aligned lower rates of injury were experienced. Discussion and conclusion: The four value-in-actions must all be present and work together in a self-reinforcing manner to engage workers and managers in achieving safe production. Practical application: Managers of both operations and safety functions do impact safety outcomes such as reducing injuries by creating a participatory environment that encourage learning that improves both safety and production routines.     

Crash risk factors for interstate large trucks in North Carolina

Introduction: Provide an updated examination of risk factors for large truck involvements in crashes resulting in injury or death. Methods: A matched case–control study was conducted in North Carolina of large trucks operated by interstate carriers. Cases were defined as trucks involved in crashes resulting in fatal or non-fatal injury, and one control truck was matched on the basis of location, weekday, time of day, and truck type. The matched-pair odds ratio provided an estimate of the effect of various driver, vehicle, or carrier factors. Results: Out-of-service (OOS) brake violations tripled the risk of crashing; any OOS vehicle defect increased crash risk by 362%. Higher historical crash rates (fatal, injury, or all crashes) of the carrier were associated with increased risk of crashing. Operating on a short-haul exemption increased crash risk by 383%. Antilock braking systems reduced crash risk by 65%. All of these results were statistically significant at the 95% confidence level. Other safety technologies also showed estimated benefits, although not statistically significant. Conclusions: With the exception of the finding that short-haul exemption is associated with increased crash risk, results largely bolster what is currently known about large truck crash risk and reinforce current enforcement practices. Results also suggest vehicle safety technologies can be important in lowering crash risk. This means that as safety technology continues to penetrate the fleet, whether from voluntary usage or government mandates, reductions in large truck crashes may be achieved. Practical application: Results imply that increased enforcement and use of crash avoidance technologies can improve the large truck crash problem.     

Incidence of injury in children and adolescents with intellectual and developmental disability

Introduction: Children and adolescents living with intellectual and developmental disability (IDD) have a higher risk of experiencing morbidities and premature death when compared to children and adolescents living without IDD. Childhood injuries are a leading cause of morbidity and death, yet there are limited studies that explore the prevalence of childhood injuries for individuals living with IDD. The purpose of this study was to analyze Ontario health administrative data to identify and compare rates of injury resulting in hospitalization in children and adolescents living with and without IDD. Methods: This is a cross-sectional study of all Ontarians aged 0–19 years with and without IDD. The outcome of interest was the rate of injury resulting in hospitalization. Results: This study found that children and adolescents with IDD had 1.79 (CI 1.66, 1.92) times higher rates of both intentional and unintentional injuries that resulted in hospitalization when compared to children and adolescents without IDD. Hospitalizations for self-harm related injuries were 3.16 (CI 3.09, 3.23) times higher in the IDD group. Conclusion: Children and adolescents with IDD have a higher risk of sustaining serious injuries, particularly injuries resulting from self-harm. Practical Applications: This study provides evidence of increased injury related hospitalizations for children and adolescents with IDD when compared to their peers without IDD.     

Characteristics of construction firms at risk for future workers' compensation claims using administrative data systems,Washington State

Introduction: Construction is high-hazard industry, and continually ranks among those with the highest workers' compensation (WC) claim rates in Washington State (WA). However, not all construction firms are at equal risk. We tested the ability to identify those construction firms most at risk for future claims using only administrative WC and unemployment insurance data. Methods: We collected information on construction firms with 10–50 average full time equivalent (FTE) employees from the WA unemployment insurance and WC data systems (n = 1228). Negative binomial regression was used to test the ability of firm characteristics measured during 2011–2013 to predict time-loss claim rates in the following year, 2014. Results: Claim rates in 2014 varied by construction industry groups, ranging from 0.7 (Land Subdivision) to 4.6 (Foundation, Structure, and Building Construction) claims per 100 FTE. Construction firms with higher average WC premium rates, a history of WC claims, increasing number of quarterly FTE, and lower average wage rates during 2011–2013 were predicted to have higher WC claim rates in 2014. Conclusions: We demonstrate the ability to leverage administrative data to identify construction firms predicted to have future WC claims. This study should be repeated to determine if these results are applicable to other high-hazard industries. Practical Applications: This study identified characteristics that may be used to further refine targeted outreach and prevention to construction firms at risk.     

Assessing disabling and non-disabling injuries and illnesses using accepted workers compensation claims data to prioritize industries of high risk for Oregon young workers

Introduction: Young workers are especially vulnerable to occupational injuries and illnesses. There is a continued need to investigate injury burden among young workers across demographics and industry to inform targeted interventions. Workers compensation (WC) claims are important for quantifying work-related injuries and illnesses, however published studies have focused on disabling claims. This study extended previous research on Oregon young workers by including the most recent WC claims data to identify patterns of injury and high risk industries. Methods: We obtained all accepted disabling claims (N = 13,360) and a significant portion of non-disabling claims (N = 24,660) on workers aged 24 years and under from 2013 to 2018. Claim count, rate and cost were calculated by year, age, gender, industry, and injury type. A prevention index (PI) method was used to rank industries in order to inform prevention efforts. Results: Average annual disabling and non-disabling claim rates were 111.6 and 401.3 per 10,000 young workers. Workers aged 19–21 (disabling: 119.0 per 10,000 and non-disabling: 429.3) and 22–24 years (115.7 and 396.4) and male workers (145.3 and 509.0) had higher claim rates than workers aged 14–18 (80.6 and 297.0) and female workers (79.8 and 282.9). The most frequent injury types were “struck by/against” (35.6%) and “work-related musculoskeletal disorders (WMSDs)” (19.5%). High risk industries included agriculture, construction, and manufacturing for both genders combined. For female young workers, the highest risk industry was healthcare. Conclusions: This study demonstrated the added value of non-disabling WC claims data. Using both disabling and non-disabling data and PI method, agriculture, construction, manufacturing and healthcare industries were identified as priority workplaces to prevent common and costly injuries among Oregon young workers. Practical Applications: While the industries identified are considered hazardous for all workers, findings in this study can guide targeted research and prevention efforts specific to young workers.     

Organizational safety: which management practices are most effective in reducing employee injury rates?

PROBLEM: While several management practices have been cited as important components of safety programs, how much does each incrementally contribute to injury reduction? This study examined the degree to which six management practices frequently included in safety programs (management commitment, rewards, communication and feedback, selection, training, and participation) contributed to a safe work environment for hospital employees. METHOD: Participants were solicited via telephone to participate in a research study concerning hospital risk management. Sixty-two hospitals provided data concerning management practices and employee injuries. RESULTS: Overall, the management practices reliably predicted injury rates. A factor analysis performed on the management practices scale resulted in the development of six factor scales. A multiple regression performed on these factor scales found that proactive practices reliably predicted injury rates. Remedial measures acted as a suppressor variable. DISCUSSION: While most of the participating hospitals implemented reactive practices (fixing problems once they have occurred), what differentiated the hospitals with low injury rates was that they also employed proactive measures to prevent accidents. IMPACT ON INDUSTRY: The most effective step that hospitals can take is in the front-end hiring and training of new personnel. They should also ensure that the risk management position has a management-level classification. This study also demonstrated that training in itself is not adequate.     

Driver licensing,motor-vehicle crashes,and moving violations among older adults

IntroductionDriving is important for well-being among older adults, but age-related conditions are associated with driving reduction or cessation and increased crash risk for older drivers. Our objectives were to describe population-based rates of older drivers’ licensing and per-driver rates of crashes and moving violations.Methods: We examined individual-level statewide driver licensing, crash, and traffic citation data among all New Jersey drivers aged ≥ 65 and a 35- to 54-year-old comparison group during 2010–2014. Rate ratios (RR) of crashes and moving violations were estimated using Poisson regression.Results: Overall, 86% of males and 71% of females aged ≥ 65 held a valid driver’s license. Older drivers had 27% lower per-driver crash rates than middle-aged drivers (RR: 0.73, 95% CI: 0.73, 0.74)—with appreciable differences by sex—but 40% higher fatal crash rates (RR: 1.40 [1.24, 1.58]). Moving violation rates among older drivers were 72% lower than middle-aged drivers (RR: 0.28 [0.28, 0.28]).Conclusion: The majority of older adults are licensed, with substantial variation by age and sex. Older drivers have higher rates of fatal crashes but lower rates of moving violations compared with middle-aged drivers.Practical applications: Future research is needed to understand the extent to which older adults drive and to identify opportunities to further reduce risk of crashes and resultant injuries among older adults.     

Occupational injury rates among Norwegian farmers: A sociotechnical perspective

Introduction: This study addressed relative injury risk among Norwegian farmers, who are mostly self-employed and run small farm enterprises. The aim was to explore the relative importance of individual, enterprise, and work environment risks for occupational injury and to discuss the latent conditions for injuries using sociotechnical system theory. Method: Injury report and risk factors were collected through a survey among Norwegian farm owners in November 2012. The response rate was 40% (n = 2,967). Annual work hours were used to calculate injury rates within groups. Poisson regression using the log of hours worked as the offset variable allowed for the modeling of adjusted rate ratios for variables predictive of injury risk. Finally, safety climate measures were introduced to assess potential moderating effects on risk. Results: Results showed that the most important risk factors for injuries were the design of the workplace, type of production, and off-farm work hours. The main results remained unchanged when adding safety climate measures, but the measures moderated the injury risk for categories of predominant production and increased the risk for farmers working with family members and/or employees. An overall finding is how the risk factors were interrelated. Conclusions: The study identified large structural diversities within and between groups of farmers. The study drew attention to operating conditions rather than individual characteristics. The farmer’s role (managerial responsibility) versus regulation and safety climate is important for discussions of injury risk. Practical Applications: We need to study sub-groups to understand how regulation and structural changes affect work conditions and management within different work systems, conditioned by production. It is important to encourage actors in the political-economic system to become involved in issues that were found to affect the safety of farmers.     

Bicyclist injury severity in traffic crashes: A spatial approach for geo-referenced crash data to uncover non-stationary correlates

Introduction: Bicyclists are among vulnerable road users with their safety a key concern. This study generates new knowledge about their safety by applying a spatial modeling approach to uncover non-stationary correlates of bicyclist injury severity in traffic crashes. Method: The approach is Geographically Weighted Ordinal Logistic Regression (GWOLR), extended from the regular Ordered Logistic Regression (OLR) by incorporating the spatial perspective of traffic crashes. The GWOLR modeling approach allows the relationships between injury severity and its contributing factors to vary across the spatial domain, to account for the spatial heterogeneity. This approach makes use of geo-referenced data. This study explored more than 7,000 geo-referenced bicycle--motor-vehicle crashes in North Carolina. Results: This study performed a series of non-stationarity tests to identify local relationships that vary substantially across the spatial domain. These local relationships are related to the bicyclist (bicyclist age, bicyclist behavior, bicyclist intoxication, bicycle direction, bicycle position), motorist (driver age, driver intoxication, driver behavior, vehicle speed, vehicle type) and traffic (traffic volume). Conclusions: Results from the regular OLR are in general consistent with previous findings. For example, an increased bicyclist injury severity is associated with older bicyclists, bicyclist being intoxicated, and higher motor-vehicle speeds. Results from the GWOLR show local (rather than global) relationships between contributing factors and bicyclist injury severity. Practical Applications: Researchers and practitioners may use GWOLR to prioritize cycling safety countermeasures for specific regions. For example, GWOLR modeling estimates in the study highlighted the west part (from Charlotte to Asheville) of North Carolina for increased bicyclist injury severity due to the intoxication of road users including both bicyclists and drivers. Therefore, if a countermeasure is concerned with the road user intoxication, there may be a priority for the region from Charlotte to Asheville (relative to other areas in North Carolina).     

Traumatic brain injury mortality among U.S. children and adolescents ages 0–19 years, 1999–2017

IntroductionTo examine recent traumatic brain injury (TBI) mortality changes among Americans aged 0–19 years by sex, age, urbanicity, state, and intent/causes of injury. Method: TBI mortality per 100,000 population and average annual percent changes (AAPCs), plus 95% confidence intervals (CIs) based on Joinpoint regression models. Results: Age-adjusted TBI mortality among Americans aged 0–19 years declined consistently, though at varying rates between 1999 and 2013 (AAPC = −4.8%, 95%CI: −6.3%, −3.2%), and then significantly increased from 4.42 per 100,000 population in 2013 to 5.17 per 100,000 population in 2017 (AAPC = 3.4%, 95% CI: 1.7%, 5.1%). During the study time period, boys, rural children, and youth aged 15–19 years had higher TBI mortality rates than girls, urban children, and younger children, respectively. TBI mortality from unintentional transport crashes decreased substantially in all age groups between 1999 and 2017, and especially from 1999 to 2010. TBI mortality from suicide increased significantly from 2008 to 2017 in the 10–14-year age group (AAPC = 14.6%, 95% CI: 12.6%, 16.6%) and from 2007 to 2017 in the 15–19-year age group (AAPC = 6.3%, 95% CI: 3.8%, 8.7%). Unintentional transport crashes were the leading cause of TBI-related mortality in 46 states in 1999, but by 2017, suicide became the first leading cause in 14 states. Conclusions: Pediatric TBI mortality declined consistently between 1999 and 2013 and increased significantly from 2013 to 2017, driven primarily by the mortality decrease from unintentional transport crashes and increase in suicide mortality. The spectrum of leading causes of pediatric TBI mortality changed across age groups and over time from 1999 to 2017. Practical Applications: TBI mortality increases in the United States since 2013 are driven primarily by increasing suicide rates, a trend that merits the attention of policy-makers and injury researchers. Action should be taken to curb growing TBI mortality rates among adolescents aged 10–19 years.     

A qualitative investigation of factors affecting school district administrators’ decision to adopt a national young worker curriculum

Introduction: Even though the majority of youth in the U.S. work, and workers under the age of 18 are seriously injured on the job at higher rates when compared to adults, most adolescents lack instruction on workplace safety and health. Method: This qualitative study examines the extent to which selected U.S. school districts provide workplace safety and health instruction to students and explores the factors that influence districts’ decision to adopt a free, foundational occupational safety and health (OSH) curriculum. Results: Results from key informant interviews conducted with a purposive sample of 34 school administrators revealed that only a third of the districts have at least 75% of their students receive some instruction on workplace safety and health, while 15% indicated they provide no instruction on this topic. District staff who indicated that they provide OSH instruction stated that it is most often taught through career and technical education (CTE; 65%) and/or health classes (26%). They believed the benefits of providing this instruction include assisting students to get jobs (38%) and helping students learn about safety (32%), while competing demands (44%) and time constraints (41%) were identified as barriers to providing OSH education to students. Conclusions: Given the importance of work to teens and their increased risk of work injury, interested stakeholders—including parents, teachers, employers, and the public health community—should promote the inclusion of workplace safety and health instruction in U.S. secondary schools. Practical Applications: This research fills a gap in current knowledge about the extent to which OSH is currently taught within U.S. secondary schools, enumerates barriers and facilitators to the inclusion of workplace safety and health instruction in schools, presents a free, foundational curriculum in workplace safety and health, and provides directions for future research on the vital role schools can play in preparing the future workforce for safe and healthy employment.     

Why is the rate of annual road fatalities increasing? A unit record analysis of New Zealand data (2010–2017)

IntroductionRecent increases in road crashes have reversed New Zealand’s formerly declining crash rates to produce annual fatal and serious injury counts that are 49% higher than the lowest rates achieved in 2013. Method: We model twenty-one factors in fatal and serious injury crashes, four years before and after 2013 using logistic regression. Three major factors are significantly different in the period after 2013, when crash rates increased: (1) alcohol as a cause, (2) learner licence holders, and (3) a regional effect for Auckland. Newly defined speed zones are a more common setting for crashes in the period of upturn but there is no coinciding elevated likelihood of ‘speed as a causal factor’. Three factors related to road safety were less common: aged under 25-years old, fatigue, and not wearing a seatbelt. Results: Results are compared to rates of prosecutions for alcohol-related driving offences over this period. It is possible that New Zealand’s successful road safety initiatives of the past have been undermined by reduced levels of enforcement and an unexpected outcome from the graduated driving licence system.     

How do organizational practices relate to perceived system safety effectiveness? Perceptions of safety climate and co-worker commitment to safety as workplace safety signals

Introduction: Integrating safety climate research with signaling theory, we propose that individual perceptions of safety climate signal the importance of safety in the organization. Specifically, we expect that three work-related organizational practices (training effectiveness, procedure effectiveness, and work pressure) relate to the broader risk control system in the workplace via individual perceptions of safety climate as a broad management signal. Further, we expect this broad management signal interacts with a local environmental signal (co-worker commitment to safety) to amplify or diminish perceived system safety effectiveness. Method: In a field study of oil and gas workers (N = 219; Study 1), we used mediation modeling to determine the relationships between work-related organizational practices, perceived safety climate, and perceived safety system effectiveness. In a field study of railway construction workers (N = 131; Study 2), we used moderated mediation modeling to explore the conditional role of co-worker commitment to safety. Results: We found that training effectiveness, procedure effectiveness, and work pressure predicted perceived system safety effectiveness indirectly via perceived safety climate (Studies 1 and 2) and that these indirect paths are influenced by co-worker commitment to safety (Study 2). Conclusions: Findings suggest that perceived safety climate is driven in part by work practices, and that perceived safety climate (from managers) and co-worker commitment to safety (from the local environment) interact to shape workplace safety system effectiveness. Practical applications: The insight that training, procedures, and work pressure are meaningful predictors of perceived safety climate as a signal suggests that organizations should be cognizant of the quality of work-related practices for safety. The insight we offer on the competing versus complimentary nature of managerial safety signals (perceived safety climate) and co-worker safety signals (co-worker commitment to safety) could also be used by safety personnel to develop safety interventions directed in both areas.     

Horseback riding-related injuries treated in emergency departments: Risk factors and prevention strategies

IntroductionDespite inherit dangers of horseback riding (HBR), research on HBR-related injuries is sparse. This study used both quantitative and qualitative methods to (1) examine HBR-related injuries treated in emergency departments (EDs) and associated risk factors and (2) explore HBR-related injury experiences and recommendations for prevention strategies from the perspective of riders. Method: We retrospectively analyzed data from the Nationwide Emergency Department Sample (NEDS), identifying HBR-related ED visits between 2010 and 2014. Additionally, we conducted 10 phone interviews with active horseback riders to understand their experiences and perspectives regarding HBR-related injuries and recommendations for prevention measures. Results: A total of 21,899 ED visits for HBR-related injuries were identified. When weighted, these represented 100,964 ED visits in the United States. Females had a consistently higher proportion of ED visits compared to males across the study period, with the proportion of ED visits being highest in females aged 15–19. Most injuries (85.9%) were treated and released from the ED. Three primary themes were identified as key to the prevention of HBR-related injuries: (1) rider safety (e.g., use of protective equipment), (2) external factors (e.g., awareness of environment), and (3) rider and horse interactions (e.g., matching skill level of the rider to the horse). Conclusions: Results indicate that HBR-related injuries treated in EDs are prevalent, with female riders aged 15–19 years having the highest proportion of injuries treated in EDs. Practical Applications: There is a critical need for injury prevention programs that not only promote the use of protective equipment, but that also educate horseback riders on horse behavior, the proper handling of horses, and safe riding practices.     

Does time of day matter at highway work zone crashes?

Introduction: It is widely agreed that highway work zones pose significant threats to road users because driving conditions in work zones are quite different from the normal ones, particularly when traffic volumes approach a highway capacity. Therefore, work zone safety is a critical aspect for state agencies and traffic engineers. Method: In the current study, a total of 10,218 crashes that occurred in highway work zones in the state of Washington for the period between 2007 and 2013 were used. Time of day is disaggregated into four subgroups: (1) Morning from 6:00 to 11:00 a.m. (2) Midday from 12:00 to 5:00 p.m. (3) Night from 6:00 to 11:00 p.m., and (4) Late night from 12:00 to 5:00 a.m. Then, four mixed logit models were estimated to account and correct for heterogeneity in the crash data by considering three injury severity levels: severe injury, minor injury, and no injury. Results: The estimation results reveal that most contributing factors are uniquely significant in a specific time of day period, whereas three factors affect injury severity regardless of time of day such as the indicators of not deployed airbag, one passenger vehicle involved in the crash, and rear-end collision. Further, some factors were found to affect injury severity into two or three time periods, such as female drivers that found to decrease the probability of no injury in morning and night time periods, while increasing severe injury outcome in midday time. Conclusions: The effect of time of day on injury severity of work-zone related crashes should be modeled separately rather than using a holistic model. Practical applications: As a starting point, findings of the current study can be used by transportation officials to reduce fatalities and injuries of work zone crashes by identifying factors that uniquely contribute to each time of day period.     

Development of injury risk models to guide CT evaluation in the emergency department after motor vehicle collisions

Abstract

Objective: The clinical evaluation of motor vehicle collision (MVC) victims is challenging and commonly relies on computed tomography (CT) to detect internal injuries. CT scans are financially expensive and each scan exposes the patient to additional ionizing radiation with an associated, albeit low, risk of cancer. Injury risk prediction based on regression modeling has been to be shown to be successful in estimating Injury Severity Scores (ISSs). The objective of this study was to (1) create risk models for internal injuries of occupants involved in MVCs based on CT body regions (head, neck, chest, abdomen/pelvis, cervical spine, thoracic spine, and lumbar spine) and (2) evaluate the performance of these risk prediction models to predict internal injury.

Methods: All Abbreviated Injury Scale (AIS) 2008 injury codes were classified based on which CT body region would be necessary to scan in order to make the diagnosis. Cases were identified from the NASS-CDS. The NASS-CDS data set was queried for cases of adult occupants who sought medical care and for which key crash characteristics were all present. Forward stepwise logistic regression was performed on data from 2010–2014 to create models predicting risk of internal injury for each CT body region. Injury risk for each region was grouped into 5 levels: very low (<2%), low (2–5%), medium (5–10%), high (10–20%), and very high (20%). The models were then tested using weighted data from 2015 in order to determine whether injury rates fell within the predicted risk level.

Results: The inclusion and exclusion criteria identified 5,477 cases in the NASS-CDS database. Cases from 2010–2014 were used for risk modeling (n?=?4,826). Seven internal injury risk models were created based on the CT body regions using data from 2010–2014. These models were tested against data from 2015 (n?=?651). In all CT body regions, the majority of occupants fell in the very low or low predicted injury rate groups, except for the head. On average, 57% of patients were classified as very low risk and 15% as low risk for each body region. In most cases the actual rate of injury was within the predicted injury risk range. The 95% confidence interval overlapped with predicting injury risk range in all cases.

Conclusion: This study successfully demonstrated the ability for internal injury risk models to accurately identify occupants at low risk for internal injury in individual body regions. This represents a step towards incorporating telemetry data into a clinical tool to guide physicians in the use of CT for the evaluation of MVC victims.     

Highway safety assessment and improvement through crash prediction by injury severity and vehicle damage using Multivariate Poisson-Lognormal model and Joint Negative Binomial-Generalized Ordered Probit Fractional Split model

Introduction: Predicting crash counts by severity plays a dominant role in identifying roadway sites that experience overrepresented crashes, or an increase in the potential for crashes with higher severity levels. Valid and reliable methodologies for predicting highway accidents by severity are necessary in assessing contributing factors to severe highway crashes, and assisting the practitioners in allocating safety improvement resources. Methods: This paper uses urban and suburban intersection data in Connecticut, along with two sophisticated modeling approaches, i.e. a Multivariate Poisson-Lognormal (MVPLN) model and a Joint Negative Binomial-Generalized Ordered Probit Fractional Split (NB-GOPFS) model to assess the methodological rationality and accuracy by accommodating for the unobserved factors in predicting crash counts by severity level. Furthermore, crash prediction models based on vehicle damage level are estimated using the same two methodologies to supplement the injury severity in estimating crashes by severity when the sample mean of severe injury crashes (e.g., fatal crashes) is very low. Results: The model estimation results highlight the presence of correlations of crash counts among severity levels, as well as the crash counts in total and crash proportions by different severity levels. A comparison of results indicates that injury severity and vehicle damage are highly consistent. Conclusions: Crash severity counts are significantly correlated and should be accommodated in crash prediction models. Practical application: The findings of this research could help select sound and reliable methodologies for predicting highway accidents by injury severity. When crash data samples have challenges associated with the low observed sampling rates for severe injury crashes, this research also confirmed that vehicle damage can be appropriate as an alternative to injury severity in crash prediction by severity.