Investigation of contributing factors to extremely severe traffic crashes using survival theory

This study aimed to investigate the contributing factors to serious casualty crashes in China. Crashes with deaths greater than 10 people are defined as serious casualty crashes in China. The serious casualty crash data were collected from 2009 to 2014. The random forest analysis was first conducted to select the candidate variables that affect the risks of serious casualty crashes. The Bayesian random parameters accelerated failure time (AFT) model was then developed to link the probability of the serious casualty crash with road geometric conditions, pavement conditions, environmental characteristics, collision characteristics, vehicle conditions, and driver characteristics. The AFT model estimation results indicate that overload driving, country road, northwest china region, turnover crash, private car, snowy or icy road surface and sight distance conditions have significant fixed effects on the likelihood of serious casualty crashes. In addition to these fixed-parameter variables, freeway, clear weather conditions, coach drivers, and upgrade horizontal curve affect the likelihood of serious casualty crashes with varying magnitude across observations. One of the important findings is that the serious casualty crash likelihood does not always decrease with an increase in the driving experience (number of years driven). Before the inflection point of 7 years, the serious casualty crash likelihood increases as the driving experience grows. The results of this study can help to develop effective countermeasures and policy initiatives for the prevention of serious casualty crashes.     

Under-reporting of road traffic crash data in Ghana

Having reliable estimates of the shortfalls in road traffic crash data is an important prerequisite for setting more realistic targets for crash/casualty reduction programmes and for a better appreciation of the socio-economic significance of road traffic crashes. This study was carried out to establish realistic estimates of the overall shortfall (under-reporting) in the official crash statistics in Ghana over an eight-year period (1997–2004). Surveys were conducted at hospitals and among drivers to generate relevant alternative data which were then matched against records in police crash data files and the official database. Overall shortfalls came from two sources, namely, ‘non-reporting’ and ‘under-recording’. The results show that the level of non-reporting varied significantly with the severity of the crash from about 57% for property damage crashes through 8% for serious injury crashes to 0% for fatal crashes. Crashes involving cyclists and motorcyclists were also substantially non-reported. Under-recording on the other hand declined significantly over the period from an average of 37% in 1997–1998 to 27% in 2003–2004. Thus, the official statistics of road traffic crashes in Ghana are subject to significant shortfalls that need to be accounted for. Correction factors have therefore been suggested for adjusting the official data.     

Morbidity and mortality from road traffic crashes in children in Metro West,City of Cape Town – 2014

The road traffic crash injury burden significantly impacts the lives of South African children. This study aimed to assess the fatal and non-fatal pattern of road traffic crash injury of children under 13 years old from Metro West, City of Cape Town, from 1 January until 31 December 2014. The data were stratified by age, sex and mechanism of road traffic crash. The overall mortality rate was 8.7 per 100 000 population and pedestrians contributed the most to this burden (72.5%). There were more male children involved in a road traffic crash (p?=?0.0001). The greatest proportion of fatal and non-fatal road traffic crash injuries was observed in children aged 5–9 years. Fractures contributed to the greatest rate of years lived with disability (3.0 years of life lived with disability per 100 000). Our study found that the burden of road traffic crashes primarily affects male pedestrians aged 5–9 years old.     

公路旅游交通量预测研究

分析公路旅游交通量预测中的影响因素,介绍了国内外常用的交通量预测思路与方法,对各种方法进行了综合评述,并通过实例对公路旅游交通量进行了预测。     

Estimating road traffic injuries in Jinja district,Uganda, using the capture-recapture method

ABSTRACT

Road traffic injuries (RTIs) are commonly under-reported in low-and-medium-income countries. This study aimed to estimate the number of RTIs and determine the magnitude of under-reporting by traffic police and hospital registries. A two-source capture-recapture method was applied to RTI data from police and hospital registries. Seven matching variables; sex of the injured, date, place, time, day of crash and road user type were used to get the matched cases. Police independently reported 46 RTIs and the hospitals reported 206 RTIs. Using the capture-recapture analysis, both sources estimated 313 RTIs (95% CI 273–343). The police registry captured 14.4% of the estimated number of RTIs and the hospitals captured 60.4%. The estimated number of RTIs was higher than reported by either the police or the hospitals alone. Neither the police nor the hospitals provided accurate data on RTIs, calling for the strengthening of both sources of data.     

Observed and unobserved correlation between crash avoidance manoeuvers and crash severity

Understanding drivers’ responses to critical events, analyzing drivers’ abilities to perform corrective manoeuvers, and investigating the correlation between these manoeuvers and crash severity provide the opportunity of increasing the knowledge about how to avoid crash occurrence or at least mitigate crash severity. We extend existing research on the determinants of engaging in crash avoidance manoeuvers by considering that observable and unobservable factors relate to both the selection of corrective manoeuvers and the severity outcome. Accordingly, we propose a joint multinomial-logit ordered-probit model of single-vehicle crashes extracted from the NASS GES database for the years 2005–2009. Results show (1) the existence of unobserved correlation between crash avoidance manoeuvers and crash severity, and (2) the link between drivers’ attributes, risky driving behaviour, road characteristics, and environmental conditions, with the propensity to engage in crash avoidance manoeuvers and experience severe crash outcomes.     

Laypeople roles at road traffic crash scenes: a systematic review

This study aimed to identify the roles of laypeople at road traffic injuries (RTIs). A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The key words of ‘laypeople’, ‘layman’, ‘layperson’, ‘bystander’, ‘first responder’, ‘lay first responder’, ‘road traffic’, ‘road traffic injury’, ‘crash injury’, ‘crash scene’, ‘emergency’, ‘trauma care’, and ‘prehospital trauma care’ were used in combination with the Boolean operators OR and AND. We did electronic search on Google Scholar, PubMed, ISI Web of Science, CINAHL, Science Direct, Scopus, ProQuest. Based on the reviewed studies, some factors such as cultural conditions, knowledge, relief agencies, and demographic factors affect the interventions of laypeople at the crash scene in functional areas. Regarding the permanent presence of people at the crash scene, the present study can provide an opportunity to reduce different side effects of RTIs imposed on the society.     

Identifying the factors contributing to the severity of truck-involved crashes

To address the dilemma between the need for truck transportation and the costs related to truck-involved crashes, the key is to identify the risk factors that significantly affect truck-involved crashes. The objective of this research is to estimate the effects of the characteristics of traffic, driver, geometry, and environment on severity of truck-involved crashes. Based on four crash severity categories (fatal/incapacitating, non-incapacitating, possible injury, and no injury/property damage only), a multinomial logit model is conducted to identify the risk factors. The investigation of risk ratios indicates that lower traffic volume with higher truck percentage is associated with more serious traffic crash with fatal/incapacitating injury while a non-standard geometric design is the main cause of non-incapacitating crashes. The influences of weather are significant for the possible-injury crashes while driver condition is the principal cause of no-injury/property-damage-only crashes. In addition, the statistical results demonstrate that the influence of the truck percentage is significant. One-unit change in the truck percentage will cause more than one times probability of being in an injury.     

Effects of pricing on Internet user behavior

The INternet Demand EXperiment (INDEX) conducts experiments to measure demand for quality-differentiated Internet access as a function of bandwidth, traffic volume, applications, and pricing structure. This paper presents an overview of results based on aggregated data from five pricing experiments. In these experiments, pricing is based either on time, volume, a combination of both, or a flat-rate buy out option. Quality of Service (QoS) is differentiated by varying bandwidth for incoming and outgoing traffic. After describing the experimental design and characterizing our subject pool using demographic data, we examine the change in service usage by comparing the five experiments in terms of traffic generation, QoS selection, and expenditure.     

Effect of driver,roadway, collision,and vehicle characteristics on crash severity: a conditional logistic regression approach

The aim of the study is to examine the factors that appear to have a higher potential for serious injury or death of drivers in traffic accidents in Turkey, such as collision type, roadway surface, vehicle speed, alcohol/drug use, and restraint use. Driver crash severity is the dependent variable of this study with two categories, fatal and non-fatal. Due to the binary nature of the dependent variable, a conditional logistic regression analysis was found suitable. Of the 16 independent variables obtained from Turkish police accident reports, 11 variables were found most significantly associated with driver crash severity. They are age, education level, restraint use, roadway condition, roadway type, time of day, collision location, collision type, number and direction of vehicles, vehicle speed, and alcohol/drug use. This study found that belted drivers aged 18–25 years involving two vehicles travelling in the same direction, in an urban area, during the daytime, and on an avenue or a street have better chances of survival in traffic accidents.     

A study of factors affecting intersection crash frequencies using random-parameter multivariate zero-inflated models

Recent research demonstrates the appropriateness of multivariate regression models in crash count modelling when one specific type of crash counts needs to be analysed, since they can better handle the correlated issues in multiple crash counts. In this paper, a random-parameter multivariate zero-inflated Poisson (RMZIP) regression model is proposed as an alternative multivariate methodology for jointly modelling crash counts simultaneously. Using this RMZIP model, we are able to account for the heterogeneity due to the unobserved roadway geometric design features and traffic characteristics. Our formulation also has the merit of handling excess zeros in correlated crash counts, a phenomenon that is commonly found in practice. The Bayesian method is employed to estimate the model parameters. We use the proposed modelling framework to predict crash frequencies at urban signalized intersections in Tennessee. To investigate the model performances, three models – a fixed-parameter MZIP model, a random-parameter multivariate negative binomial (RMNB) model, and a random-parameter multivariate zero-inflated negative binomial (RMZINB) model – have been employed as the comparison methods. The comparison results show that the proposed RMZIP models provide a satisfied statistical fit with more variables producing statistically significant parameters. In other word, the RMZIP models have the potential to provide a fuller understanding of how the factors affect crash frequencies on specific roadway intersections. A variety of variables are found to significantly influence the crash frequencies by varying magnitudes. These variables result in random parameters and thereby their effects on crash frequencies are found to vary significantly across the sampled intersections.     

Impact of traffic citations to reduce truck crashes on challenging roadway geometry

Wyoming's Interstate 80 has one of the highest truck crash rates in the United States. This is due to a variety of reasons, including high percentage of truck traffic, adverse weather conditions and mountainous terrain. These factors have caused the Wyoming Highway Patrol (WHP) to spend extensive resources on inspecting commercial vehicles and enforcement of traffic laws in this corridor. This study estimated the correlation between traffic citations and truck crashes. In addition, the paper evaluated the increased risk of truck crashes in adverse weather and road conditions. The explanatory variables included geometric features, weather condition, traffic volume and types of citations. This research concluded that speeding related citations and truck crashes are negatively correlated, and the risk of truck crashes is significantly higher when weather is not clear, and the road is not dry.     

Fatal and serious road crashes involving young New Zealand drivers: a latent class clustering approach

The over-representation of young drivers in road crashes remains an important concern worldwide. Cluster analysis has been applied to young driver sub-groups, but its application by analysing crash occurrence is just emerging. We present a classification analysis that advances the field through a holistic overview of crash patterns useful for designing youth-targeted road safety programmes. We compiled a database of 8644 New Zealand crashes from 2002 to 2011 involving at least one 15–24-year-old driver and a fatal or serious injury for at least one road user. We considered crash location, infrastructure characteristics, environmental conditions, demographic characteristics, driving behaviour, and pre-crash manoeuvres. The analysis yielded 15 and 8 latent classes of, respectively, single-vehicle and multi-vehicle crashes, and average posterior probabilities measured the odds of correct classification that revealed how the identified clusters contain mostly crashes of a particular class and all the crashes of that class. The results raised three major safety concerns for young drivers that should be addressed: (1) reckless driving and traffic law violations; (2) inattention, error, and hazard perception problems; and (3) interaction with road geometry and lighting conditions, especially on high-speed open roads and state highways.     

高速公路对哈大齐工业走廊影响研究

高速公路因其自身特性在国民经济中具有重要作用。黑龙江省高速公路的加快建设促进了哈大齐工业走廊经济发展、社会发展、商品流通及沿线旅游资源开发。高速公路在提高区域综合运输能力的同时,进一步沟通了哈大齐工业走廊内哈尔滨、大庆、齐齐哈尔、肇东、安达等大中城市、交通枢纽、工业中心的联系,增强了外商投资的吸引力,有力地推动了哈大齐工业走廊经济发展,带动了相关产业的迅猛发展。