Incorporating systems thinking approach in a multilevel framework for human-centered crash analysis

Developing a safer road user behaviour index

The continuous increases in the numbers of road traffic crashes (RTC) over the years, especially in developing countries, have been a source of worry. The majority of the RTC are attributed to road user behaviours exhibited by the drivers. This study sets out to investigate the road user attitudes and behaviours in Abuja, Nigeria. A total of 1526 questionnaires were distributed, of which 321 questionnaires were completed and returned. The questionnaires tried to understand four major road user behaviours, namely use of seatbelts, drink driving, use of mobile phone while driving, and use of child restraints. The results after analysing the questionnaires showed that the majority of the road users in Abuja showed high non-compliance with the use of seatbelts, either when driving or when being driven. About 64% of the respondents admitted to not using seatbelts. Results from the cross-tabulation process showed that the high non-compliance to seatbelt usage was statistically associated with young, single road users. Around one-third of Abuja road users admitted to drink driving. Road users who were married engaged in more frequent drink driving than road users who were single, and the association was statistically significant. A high percentage of Abuja road users admitted to using mobile phones while driving and 55.8% of the total respondents admitted to not using child restraints while driving. A lack of child restraints was statistically associated more with male road users than female road users. It is recommended that stricter enforcement of road safety laws should be undertaken and that the government should provide road safety agents with the right equipment (e.g., speed guns, breathalyzers) that would aid road safety agents to perform their duties effectively in order to curb the excessive bad road user behaviours in Abuja.

BackgroundDespite substantial progress, motor vehicle crashes remain a leading killer of US children. Previously, we documented significant positive impacts of Safe Routes to School interventions on school-age pedestrian and pedalcyclist...

Objective To assess the degree to which speed limits are being set in accordance with the Safe System, with fatal crash rates remaining negligible regardless of speed limit. A further objective was to examine the reduction in fatal crashes that could be achieved if the fatal crash rate were equal to the lowest fatality rate in a common speed zone. Method Police reported crashes from 2016 to 2023 in two Australian states were used to calculate the fatal crash rate by speed limit. The analysis was conducted at three levels; combined data, by state, and by state and area. Fatal crash reductions were projected based on all speed zones having a fatal crash rate equal to that for roads with a speed limit of 50 km/h. Results The fatal crash rates were found to be non-negligible at all speed limits. Furthermore, the fatal crash rates generally increased as speed limits increased. This suggests that the speed limits in Australia do not sufficiently account for the different levels of risk found on the road network. In an 80 km/h zone, the risk of a crash being fatal is three times higher than in a 50 km/h zone and, in a 100 km/h zone, it is more than six times that of a 50 km/h zone. Of particular concern is the 110 km/h zones in South Australia, where the risk of a crash being fatal is more than 12 times higher than in a 50 km/h zone. It was found that, if the fatal crash rate for all speed zones was equal to the rate in 50 km/h zones, the number of fatal crashes would be reduced by between 46.2% and 55.5%. Conclusions Speed limits in Australia are not sufficiently matched to the risk to road users should a crash occur, with substantial increases in the fatal crash rate at speeds limits of 80 km/h and above. A uniform fatal crash rate equal to the fatal crash rate found in 50 km/h zones would halve the number of fatal crashes. Lowering the fatal crash rate in Australia could be achieved through improvements to the roads, improvements in the passive safety of vehicles, and the lowering of speed limits, or a combination of these approaches.

To analyze the characteristics of fatal ambulance crashes to assist emergency medical services (EMS) directors in objectively developing their EMS system's policy governing ambulance operations. No difference exists between the characteristics of fatal ambulance crashes during emergency and nonemergency use. Retrospective, cross-sectional, comparative analysis of ambulance crashes resulting in fatalities reported to the Fatal Accident Reporting System (FARS) from 1987 to 1990. Twenty variables, representing characteristics of fatal ambulance crashes, were selected from the National Highway Traffic Administration FARS Codebook and were evaluated using tests of significance for categorical data grouped by emergency use and nonemergency use. Crash variable categories examined included demographics, accident configuration, accident severity, vehicle description, and ambulance operator action. During the four-year study period, 109 fatal ambulance crashes occurred producing 126 deaths. Four states, New York, Michigan, California, and North Carolina, accounted for 37.5% of all fatal crashes. Seventy-five fatal crashes (69%) occurred during emergency use (EU) and 34 fatal crashes (31%) occurred during nonemergency use (NEU). The total number of fatal crashes varied in a downward trend (1987:32; 1988:24; 1989:28; 1990:25). The number of fatal EU crashes also varied in a downward trend (1987:28; 1988:16; 1989:19; 1990:12), while the number of fatal NEU crashes increased each year [1987:4; 1988:8; 1989:9; 1990:13](p = .016). Most EU fatal crashes occurred between 1200 h and 1800 h (p = .009). Most NEU fatal crashes occurred during times when light conditions were poor (p = .003). When a violation was charged to the ambulance driver (17 cited), the vehicle was more likely to be in EU (p = .056). No statistically significant differences between EU and NEU were identified by: 1) day of week; 2) season; 3) atmospheric conditions; 4) roadway surface type; 5) roadway surface condition; 6) speed limit; 7) roadway alignment; 8) relationship to junction; 9) manner of collision; 10) year manufactured; 11) vehicle role; 12) vehicle maneuver; 13) manner leaving scene; 14) extent of deformation; 15) violations charged; or 16) number of persons killed in accident. Few characteristics differentiate between fatal ambulance crashes during EU and NEU. The difference between EU and NEU were statistically significant in only three out of the 20 variables examined: 1) year occurred; 2) time of day; and 3) light condition. These data provide few objective measures that may be used to develop ambulance operation policies to decrease fatal ambulance crashes.

Objectives: The objective of the current study was to quantify the effects of the strength of US state graduated driver licensing laws and specific licensing components on the rate of teenage driver fatal crash involvements per 100,000 teenagers during 1996–2007. The strengths of state laws were rated good, fair, marginal, or poor based on a system developed previously by the Insurance Institute for Highway Safety. Methods: Analysis was based on quarterly counts of drivers involved in fatal crashes. Associations of overall ratings and individual licensing components with teenage crash rates were evaluated using Poisson regression, with the corresponding fatal crash rate for drivers ages 30–59 controlling for state- or time-dependent influences on crash rates unrelated to graduated licensing laws. Results: Compared with licensing laws rated poor, laws rated good were associated with 30 percent lower fatal crash rates among 15- to 17-year-olds. Laws rated fair yielded fatal crash rates 11 percent lower. The longer the permit age was delayed, or the longer the licensing age was delayed, the lower the estimated fatal crash rates among 15- to 17-year-olds. Stronger nighttime restrictions were associated with larger reductions, and reductions were larger for laws limiting teenage passengers to zero or one than laws allowing two or more teenage passengers or laws without passenger restrictions. After the effects of any related delay in licensure were accounted for, an increase in the minimum learner's permit holding period showed no association with fatal crash rates. An increase in required practice driving hours did not appear to have an independent association with fatal crash rates. Conclusions: Graduated licensing laws that include strong nighttime and passenger restrictions and laws that delay the learner's permit age and licensing age are associated with lower teenage fatal crash rates. States that adopt such laws can expect to achieve substantial reductions in crash deaths.

Large truck fatal crash severity segmentation and analysis incorporating all parties involved: A Bayesian network approach

This paper presents the results of an analysis focusing on large truck-involved work zone fatal crashes using seven-year crash data in the State of Florida. Decision tree/random forest models were applied to specifically detect critical crash patterns that result in a fatality outcome. Because of the imbalanced nature of crash severity data (very low frequency of fatal crashes compared with property damage only or injury), data were treated using random and systematic over-sampling techniques. Marginal effects were addressed using Shapley values to increase model explainability. From a methodological perspective, results showed that the combination of over-sampling techniques with ensemble random forests could significantly improve model performance in predicting fatal crashes (compared with conventional logistic regression models). Primary contributors included pedestrian involvement, lighting conditions, safety equipment, driver condition, driver age, and work zone locations. For pedestrian crashes, factors such as dark-not lighted conditions, distracted truck driver, and driver’s age (young drivers outside city limits, senior drivers inside city limits) were highly likely to be fatal. For non-pedestrian crashes, the combination of front airbag deployment with any restraint system other than shoulder and belt was quite likely to be fatal. Also, abnormal driver conditions increased the risk of a fatal outcome. Additionally, the presence of female drivers (as the second driver in multiple vehicle crashes) highly decreased crash severity, probably because females typically drive more carefully than males. Interestingly, truck driver actions and maneuvers as well as roadway design and other physical environment features (i.e., number of lanes, median type, roadway grade, and alignment) did not show significant contribution to the model.

A human driver determines his/her driving action by predicting future behavior of other road users based on the consideration of relative relationships and reactions between all players. To get as close as possible to human driving behavior, it is important to predict the early and long-term behavior of other road users. For this sake, many motion-based methods has been proposed, although only for short-term prediction. On the other hand, reasoning-based methods for long-term prediction have been proposed recently. However, they can only predict the latest behavior to the observation and do not consider uncertainty, which is necessary to realize smooth autonomous driving behavior. Therefore, we propose a method that predicts long-term behavior of other road users with estimated probabilities based on semantic reasoning that considers interactions among various players. For this purpose, we define an ontology that provides a conceptual description of all road users with their interactions, and infer the likely behaviors with their associated probabilities using Markov Logic Network (MLN). This framework is used with a actual vehicle as it approaches intersections, to demonstrate its applicability. Results from the real-time implementation on the vehicle, operating under controlled conditions, indicate that the proposed approach predicts a sequence of behavioral possibilities with their associated probabilities as expected.

With the increasing use of electric bikes, electric bike crashes occur frequently. Analysing the influencing factors of electric bike crashes is an effective way to reduce mortality and improve road safety. In this paper, spatial analysis is performed by geographic information system (GIS) to present the hot spots of electric bike crashes during daylight and darkness in Changsha, Hunan Province, China. Based on the Ordered Probit (OP) model, we studied the risk factors that led to different severities of electric bike crashes. The results show that the main influencing variables include age, illegal behaviour, collision type and road factors. During daylight and darkness, elderly electric bike riders over the age of 65 years have a higher probability of fatal crashes. Not following traffic signals and reverse driving are significantly related to the severity of riders' injuries. In darkness, frontal collisions are significant factors causing rider injury. In daylight, more serious crashes will be caused in bend and slope road segments. In darkness, roads with no physically separated bicycle lanes increases the risk of riders being injured. Electric bike crashes are mainly concentrated in the commercial, public service and residential areas in the main urban area. In suburbs at darkness, electric bike riders are more likely to be seriously injured. Adding protection measures, such as improved lighting, non-motorized lane facilities and interventions targeting illegal behaviour in the hot spot areas can effectively reduce the number of electric bike crashes in complex traffic.

Road characteristics and environment factors associated with motorcycle fatal crashes in Malaysia

Despite numerous past studies conducted on traffic barriers, research is still needed to analyze the performance of traffic barriers on superelevated horizontal curves. Based on the literature of traffic barrier studies, the effect of geometric features of traffic barriers (such as height and post-spacing) on crashes involving horizontal curves has not been investigated considering actual crash data analysis. This paper seeks to study the effect of various variables affecting the severity of traffic barrier crashes on horizontal curves. Geometric features of 95 miles of traffic barriers were collected, conducting a field inventory on all interstate roads in Wyoming. All the traffic barriers collected were located on horizontal curves with at least one historical crash report between 2008 and 2017. Random-parameters ordered logit was used to develop two models to investigate the factors impacting the severity of horizontal curve crashes involving side and median traffic barriers, respectively, on interstate roads. Based on the results, median box beam barriers with a post-spacing of 6.1 ft resulted in lower injury severity. Median W-beam barriers with a height taller than 31 inches were involved with a higher probability of severe collisions. Side box beam barriers located on the front side-slope were also more likely to increase the severity of crashes.

Key challenges in tram/streetcar driving from the tram driver’s perspective – A qualitative study

Examining crash injury severity and barrier-hit outcomes from cable barriers and strong-post guardrails on Alabama’s interstate highways

To re-examine and refine estimates for alcohol-related relative risk of driver involvement in fatal crashes by age and gender as a function of blood alcohol concentration (BAC) using recent data. Logistic regression was used to estimate age/gender specific relative risk of fatal crash involvement as a function of the BAC for drivers involved in a fatal crash and for drivers fatally injured in a crash, by combining crash data from the Fatality Analysis Reporting System with exposure data from the 1996 National Roadside Survey of Drivers. In general, the relative risk of involvement in a fatal vehicle crash increased steadily with increasing driver BAC in every age/gender group among both fatally injured and surviving drivers. Among 16-20 year old male drivers, a BAC increase of 0.02% was estimated to more than double the relative risk of fatal single-vehicle crash injury. At the midpoint of the 0.08% - 0.10% BAC range, the relative risk of a fatal single-vehicle crash injury varied between 11.4 (drivers 35 and older) and 51.9 (male drivers, 16-20). With only very few exceptions, older drivers had lower risk of being fatally injured in a single-vehicle crash than younger drivers, as did women compared with men in the same age range. When comparable, results largely confirmed existing prior estimates. This is the first study that systematically estimated relative risk for drink-drivers with BACs between 0.08% and 0.10% (these relative risk estimates apply to BAC range midpoints at 0.09%.) The results clearly show that drivers with a BAC under 0.10% pose highly elevated risk both to themselves and to other road users. 2000)