Traffic Safety Improvement Research Articles

Mining maritime traffic conflict trajectories from a massive AIS data

The growing volume of maritime traffic is proving a hindrance to navigational safety. Researchers have sought to improve the safety of maritime transportation by conducting statistical analysis on historical collision data in order to identify the causes of maritime collisions. However, this approach is hindered by the limited number of incidents that can be collected in a given area over a given period of time. Automatic Identification System (AIS) has made available enormous quantities of maritime traffic data. Trajectory data are collected through the electronic exchange of navigational data among ships and terrestrial and satellite base stations. Due to a massive AIS data of recording ship movement, such data provide great opportunity to discover maritime traffic knowledge of movement behavior analysis, route estimation, and the detection of anomalous behaviors. Our objective in this paper was to identify potential between-ship traffic conflicts through the discovery of AIS data. Traffic conflict refers to trajectories that could lead to a collision if the ships do not take any evasive action. In other words, conflicting trajectories can be treated as a near-collision cases for analysis. The prevention of collisions requires an efficient method by which to extract conflicting trajectories from a massive collection of AIS data. To this end, we developed a framework CCT Discovery that allows the automated identification of clusters of conflicting trajectories (CCTs) from AIS data without supervision. Experiments based on real-world data demonstrate the efficacy of the proposed framework in terms of accuracy and efficiency. For improvement in the navigational traffic safety, the discovered data of conflict trajectory can contribute to numerous applications, such as collision situation awareness and prediction, anti-collision behaviors modeling and recommendation, and conflict area analysis for maritime traffic flow management.

Safety effectiveness of truck lane restrictions: a case study on Texas urban corridors

ABSTRACTTruck lane restrictions (TLRs) have become increasingly popular throughout the United States over the last 20 years due to the improvement in traffic operations and safety, pavement life, and other associated factors. This study examines the safety performance of the TLRs that have been implemented in the North Texas region. TLR prohibit semi- trucks (trucks) from using the left-most freeway lane, or inner lane, except in passing or emergency maneuvers. This study uses 16 sites with TLR in the Dallas-Fort Worth area to conduct an observational before-after study. For safety effectiveness analysis, it is always hard to get three years before and three years after data. For immediate safety effectiveness analysis, sophisticated predictive tools could be used in estimating ‘after’ year crashes. This study used the Enhanced Interchange Safety Analysis Tool (ISATe) to supplement the limited after year crash data. This study used Empirical Bayes (EB) method due to its consideration of regression-to-mean bias. The findings show that TLRs perform an overall positive safety effectiveness for large truck-involved fatal and injury crashes for six-lane roadways. This study concludes that implementing TLR as a truck-related safety strategy which are cost-effective to implement, may contribute to improving safety on urban freeways.

Exploring crash mechanisms with microscopic traffic flow variables: A hybrid approach with latent class logit and path analysis models

Understanding the occurrence mechanisms of crashes is critical for traffic safety improvement. Efforts have been investigated to reveal the crash mechanisms and analyze the contributing factors from the aspects of vehicle, driver, and operational perspectives. In this study, special attention has been paid to the operational level analyses while bridging the research gaps of: (1) failing to identify the heterogeneous impact of microscopic traffic flow variables on crash occurrence, and (2) focusing on correlation effects without further investigations for the causal relationships. A hybrid modeling approach with latent class logit (LCL) and path analysis (PA) models was proposed to account for the heterogeneous influencing effects and reveal the causal relationships between crash occurrence and microscopic traffic flow variables. Data from Shanghai urban expressway system were utilized for the empirical analyses. First, the LCL model has concluded four latent subsets of crash occurrence influencing factors. Then, PA models were conducted to identify the concurrent relationships (direct and indirect eff ;ects) for the four sets of crash occurrence influencing factors separately. Finally, the results of the LCL model and PA models were compared and the crash-prone scenarios were inferred. And the potential safety improvement countermeasures were discussed.

Case Study - Benefits from Constructing a Grade-Separated Interchange

The paper presents the results of analyzes regarding the benefits of the planned road network development, reconstruction of a road intersection of the national road No. 25 and provincial road No. 254. Actual and forecasted traffic volumes and saturation factors on the road network were calculated based on the regional simulation transport demand model. The value of transport work performed by all vehicles traveling on this network, the value of travel time of drivers and passengers traveling during the weekday as well as the costs of impact of traffic into the environment were also determined. On this basis, a preliminary economic analysis was made as the base for a feasibility study, to proof economic benefits of such investment. Traffic analyzes, the results of which were presented in this paper, were made using the actual and prognostic four-stage regional simulation transport demand models. The authors adopted a typical trumpet-type of grade separated interchange for economic analyzes. It is a collision-free interchange, and therefore very safe in its very nature. The experience of current road practice indicates that significant improvement of road traffic safety will be the undoubted benefit resulting from the construction of such interchange. Additionally, such construction will also reduce time lost by road users in traffics. It should be noted that at present a railway at-grade crossing located in a short distance from the abovementioned intersections is the most serious source of time lost in traffic by road users. The railway line with heavy passenger and freight traffic causes each closing of the turnpikes effectively blocks traffic on main turns of above mentioned intersection. The construction of the grade separated interchange will enable collision-free intersection of the road with the railway, and thus will reduce the loss of time - a significant improvement in the functioning of the analyzed area.

Integrated Safety and Operational Analysis of the Access Design of Managed Toll Lanes

Managed lanes (MLs) have been implemented as a vital strategy for traffic management and traffic safety improvement. The majority of previous studies involving MLs have adopted a limited scope of examining the effect of MLs segments as a whole, without considering the safety and operational effects of the design of access to the MLs. In the study, several scenarios were tested using microscopic traffic simulation to determine the optimal access design while taking into consideration accessibility levels and weaving lengths. The studied accessibility levels varied from one to three along the studied network. Both safety (i.e., speed standard deviation, time-to-collision, and conflict rate) and operation (i.e., level of service, average speed, average delay) performance measures were included in the analysis. Tobit models were developed for investigating the factors that affect the safety measures. ANOVA and LOS calculations were used to evaluate traffic operation. The results of the safety and operational analysis suggested that one accessibility level is the optimal option in the nine-mile network. A weaving length between 1,000 feet and 1,400 feet per lane change was suggested based on the safety analysis. In addition, from the operation perspective, a weaving length between 1,000 feet and 2,000 feet per lane change was recommended. The results also showed that off-peak periods had better safety and operational performance (e.g., lower conflict rate, less delay) than peak periods. This study has major implications for improving MLs by recommending the optimal accessibility level and weaving length near access zones.

Road Traffic Safety in Latvia

The article discusses development trends in road traffic safety indicators in Latvia. Changes in society and vehicle fleet after the regain of independence created new situation on the roads. More dynamic vehicle fleet allowed achieving higher average speed of the traffic flow. Reduction in the service level of public transport resulted in much higher use of cars which in turn led to increased traffic flow density. Currently the use of cars in Latvia and in particular in the rural areas has become an integral part of everyday life. It is obvious, that road traffic safety improvement is a complex and complicated task. Despite some achievements during past years, general road traffic safety situation in comparison to other EU countries has still relatively big improvement potential. The article is thus aimed at showing the influence of automobilization increase on road traffic safety level and discussing the reasons for improving road traffic safety level.

Incorporating transportation safety into land use planning: Pre-assessment of land use conversion effects on severe crashes in urban China

Severe crashes (SCs) have raised significant challenges to public safety in China. Given the prevalence of urban redevelopment, there is an urgent need to incorporate transportation safety into new-phase land use planning. This study presents an approach to pre-assess the traffic safety outcomes of land use conversions by investigating the association between land use conversions and variations in SCs in urban China. Generalized structural equation modelling (GSEM) was used to construct the hierarchical relationships among the SC frequency, land uses, and SC-related features. The Wald test was then employed to examine the reshaping of SC-related features and the SC frequency variation in land use conversions. The results showed that urban residential, commercial and business and mixed residential-commercial land uses had the highest SC risk exposure levels. A set of land use conversions oriented towards these three land uses were positively associated with the SC frequency and would universally drive the reshaping of SC-related features in the traffic volume, accessibility of destinations, and spatial variations in the population and employment at the traffic analysis zone level. These types of conversions were highly sensitive to the generation of mixed traffic flows, thereby leading to a higher risk of exposure to SCs. In contrast, land use conversions were less associated with the reshaping of zonal traffic speeds. The applicability of the proposed approach and the corresponding findings in supporting land use planning strategies for traffic safety improvements in transitional cities and urban China in particular was discussed.

A Novel Framework for Sustainable Traffic Safety Programs Using the Public as Sensors of Hazardous Road Information

Traditionally, traffic safety improvement programs (TSIPs) have been based on the number of crashes at a specific location or their severity. However, the crash datasets used for such programs are obtained from the police and include two limitations: not all crashes are collected by the police (most minor and near-miss crashes are not reported), and the traditional process uses crash data recorded for the past two or three years (meaning most data inevitably include a time lag). To overcome these limitations, this study proposes a new approach for a TSIP based on citizen participation through an online survey that is broadcasted through social media. The method uses the public as sensors of hazardous road information, which means that information can be collected on individual experiences of minor crashes and latent risk factors, such as near misses and traffic conflicts. To demonstrate this approach, a case study was carried out in a small district in the city of Goyang, Korea, which has one of the highest usage rates of social media technologies. The proposed method and a traditional method were both assessed.

A Cask Evaluation Model to Assess Safety in Chinese Rural Roads

Suburban roads are an important part of China’s road network and essential infrastructure for rural development. Poorly designed road curves and scarcity of traffic signs have caused an excessively high traffic accident rate in plain topographical areas. In this study, an approach to evaluate and improve rural road traffic safety is introduced. Based on fuzzy and cask theory and weighted analysis, a cask evaluation model is built. It provides a quantitative instant method for analyzing road safety in the absence of traffic accident information or rigorous road space data, by identifying dangerous sections and key impact factors, and ultimately help to put forward traffic safety improvements. Based on the application to a specific section of Xiaodang Central Road in the Fengxian District of Shanghai, the result shows that the pavement conditions of cement-hardened dual-lane rural roads was good, but traffic safety was poor. Missing traffic signs, unreasonable road alignment, and poor roadside conditions were the main problems. Finally, improvements of the short-stave subsystem were proposed: the location of guide signs and roadside conditions should be improved, and the number and efficacy of the rural road traffic signs need to be increased, and markings should be and receive regular maintenance.

Interactions between Driving Skills on Aggressive Driving: Study among Chinese Drivers

Aggressive driving has attracted significant attention recently with the increase in related road traffic collisions occurring in China. This study aims to investigate the effect of driving skills on aggressive driving behaviors and traffic accidents to find implications for traffic safety improvement in China. A total of 735 Chinese drivers were recruited to complete a self-reported survey including demographic information, the translated Driver Skill Inventory (DSI), and Driver Aggression Indicator Scale (DAIS). Exploratory factor analysis was first conducted to investigate the factor structures of DSI and DAIS among Chinese drivers. Unlike the two-factor solution (i.e., perceptual-motor and safety skills) found in other studies, the current study result revealed a three-factor solution (i.e., perceptual-motor, safety, and emotional control skills) of DSI. Then, the interaction between DSI factors on DAIS factors, demographic variables, and the number of self-reported traffic accidents and offenses was tested by using moderated regression methods. The results revealed the interaction between perceptual-motor skills and safety skills on aggressive warnings committed by drivers themselves. The interactive effect between safety skills and emotional control skills on perceived aggressive warnings was also found. The results suggested that higher ratings of safety skills are essential for buffering the effect of high-level perceptual-motor skills and emotional control skills on aggressive driving in China. In conclusion, policy makers should be interested in understanding the effect of Chinese drivers’ skills on the aggression drivers committed and conceived in traffic. Successful intervention strategies should include all skill factors in the driver training contents.

Quantifying drivers’ visual perception to analyze accident-prone locations on two-lane mountain highways

Owing to constrained topography and road geometry, mountainous highways are subjected to frequent traffic accidents, and these crashes have relatively high mortality rates. In middle and high mountains, most roads are two-lane highways. Most two-lane mountain highways are located in rural areas in China, where traffic volume is relatively small; namely, traffic accidents are mainly related to the design of roads, rather than the impact of traffic flow. Previous studies primarily focused on the relationship between actual road geometry and traffic safety. However, some scholars put forward that there was a significant discrepancy between actual and visual perceived information. Drivers greatly depend on what they perceived by their vision to determine driving behavior. Thus, in this paper drivers’ visual lane model was established to quantify drivers’ visual perception. To further explore drivers’ perception of horizontal and vertical alignments, the visual lane model was projected onto horizontal and vertical planes in drivers’ vision respectively. The length and curvature of the visual curve were extracted as shape parameters of drivers’ visual lane models. Real vehicle driving tests were conducted on typical two-lane mountain highway sections of G318 in Tibet, China. Then the differences of visual perception at black spots and accident-free locations were analyzed and compared. In horizontal and vertical projections of visual lane model, there were 9 shape parameters have significant differences between accident-prone and accident-free locations. A probabilistic neural network (PNN) was formed to identify accident-prone locations on two-lane mountain highways. This study will lay a foundation for the improvement of traffic safety on mountain highways based on the quantification of drivers’ visual perception, during the phase of both road design and reconstruction, and can also make a contribution to the automatic driving technique.

Priority rule signalization under two visibility conditions: Driving simulator study on speed and lateral position

In literature, priority-controlled and right-hand priority intersections have rarely been compared on other elements than the number of right-of-way violations and collisions. This study investigates the effect on speed and lateral position of five priority rules under two visibility conditions at an intersection (without hierarchy between branches), which is, at this moment, a knowledge gap.Fifty participants drove five different routes in a simulator and were exposed to the following manipulations: priority to the right rule applying and indicated (road sign and road sign with road marking), priority to the right rule applying but not indicated (no sign), priority to the right rule not applying and indicated (priority road and priority at next intersection), under good and bad visibility.Results show a significant speed decrease for both situations where the priority to the right rule was indicated compared to situations with no priority to the right rule, especially when visibility was bad. Priority to the right signs with additional road marking resulted in lowest speed under both visibility conditions. For all priority rules, lateral position shifted more towards the middle of the road when visibility was bad.Since speed was higher in case of priority roads or roads with priority at next intersection, it can be concluded that a higher level of control (priority-controlled intersections) does not necessarily result in a traffic safety improvement. Therefore, policy makers should take into account the results of this study and not generally change all the priority to the right intersections by priority-controlled intersections.

Evaluation of airfield pavement evenness

The evenness of airfield pavements is one of the basic operating parameters, which characterize them. The evenness determines not only comfort of traffic along an airfield pavement, but also influences the size of dynamic effect on the pavement, hence, the safety of air operations. In addition, the evenness condition changing as a result of dynamic loads, adverse weather conditions or inappropriate airfield pavement construction technology, lead to deviations from the desired condition in the form of longitudinal and transverse unevenness. As a result, systematic and correct performance of tests is a very significant and required factor impacting the improvement of traffic safety on airfield pavements. If the data obtained through the measurements are not sufficiently reliable, they may consequently lead to making incorrect decisions, which can ultimately impact the safety of air operations.

Analysis of the spatial distribution of road accidents attended by the Mobile Emergency Service (SAMU-192) in a municipality of northeastern Brazil

This study describes the epidemiological characteristics of road accident victims attended by the Brazilian Mobile Emergency Service (SAMU-192) and located in the areas of highest accident density in the municipality of Olinda, (Pernambuco, Brazil). Kernel density estimation was used to detect spatial agglomerations of accidents. In 2015, 724 accidents occurred; of these, 73.48% of the victims were males aged 20-39 years. There was a predominance of accidents involving motorcycles (54.97%). Accident clusters were detected in the main traffic corridors, with run-over accidents located near bus terminals. Spatial analysis proved to be a relevant instrument for the identification of accident clusters and the application of effective prevention and traffic safety improvement measures.

Young drivers’ perception of adult and child pedestrians in potential street-crossing situations

Despite overall improvements in road traffic safety, pedestrian accidents continue to be a serious public health problem. Due to lack of experience, limited cognitive and motoric skills, and smaller size, children have a higher injury risk as pedestrians than adults. To what extent drivers adjust their driving behaviour to children’s higher vulnerability is largely unknown. To determine whether young male drivers’ behaviour and scanning pattern differs when approaching a child and an adult pedestrian in a potential street-crossing situation, sixty-five young (18–24) male drivers’ speed, lateral position and eye movements were recorded in a driving simulator. Results showed that fewer drivers responded by slowing down and that drivers had a higher driving speed when approaching a child pedestrian, although the time of the first fixation on both types of pedestrians was the same. However, drivers drove farther away from a child than an adult pedestrian. Additionally, fewer drivers who did not slow down fixated on the speedometer while approaching the child pedestrian. The results show that young drivers behave differently when approaching a child and an adult pedestrian, though not in a way that appropriately accounts for the limitations of a child pedestrian. A better understanding of how drivers respond to different types of pedestrians and why could contribute to the development of pedestrian detection and emergency braking systems.

Effects of Prolonged Tasks and Rest Patterns on Driver's Visual Behaviors, Driving Performance, and Sleepiness Awareness in Tunnel Environments: A Simulator Study

Driving sleepiness is one of the most important potential causes of traffic accidents, especially for long-distance drivers under monotonous conditions. In this study, 68 professional, male coach drivers were recruited to participate in 2-, 3-, and 4-h driving tasks on a simulated mountainous expressway and then were given a 15- or 30-min rest with or without music stimulus to recover. At the end of each driving task and rest period, the driver’s eye movement indicators, driving performance measures, and subjective sleepiness level were examined via eye tracking device, performance testers, and the Stanford Sleepiness Scale, respectively. One-way ANOVA was used to analyze the variation of each variable at different stages. The statistical analysis revealed that the driving duration and rest patterns have significant impacts on the driver’s visual behaviors and driving performance. The participants’ blink duration, eye closure duration, reaction time, number of incorrect action judgments, and subjective level of sleepiness significantly changed as driving time increased. Drivers recovered sufficiently after a general 30-min rest or a 15-min rest with music after 2- and 3-h driving tasks, but required a 30-min rest with music as stimulus after 4-h driving task. These results provide insight into potential strategies for traffic safety improvements among long-distance drivers.

Traffic safety improvement through implementing innovative technologies and materials in construction of roads and bridges

Abstract The paper reports data on implementing innovative technologies and materials in construction of roads and bridge structures. It is proposed to construct road pavement using nepheline sludge to improve motor road macadam shear strength. This technology helps preventing such road pavement defects as rutting, cracks and early deterioration of the road surface. It is also proposed to implement composite fiber-glass materials in construction of bridge structures on motor roads. Nowadays, the tube confined concrete technology, developed long ago, is successfully applied in building construction as a way to increase the concrete bearing capacity. Its implementation in bridge structures is limited by poor corrosion resistance of the metal casing and its poor resistance to other aggressive environmental effects. Recently, composite fiber-glass materials, including pipes (casings), have been developed and actively applied. They feature good resistance to aggressive environmental effects, great durability as compared to metal, good resistance against wall pressure. Fiber-glasses have sufficiently high strength confirmed by experimental studies listed in this paper. Using fiber-glass casings in bridge pier columns is promising due to their properties; it should improve the strength and reliability of such structures and increase their service life. The approach is also promising from the architectural and aesthetic standpoint. Moreover, application of nepheline sludge in road pavements and fiber-glass composite casings in bridge piers shall increase the reliability of transport structures during operation, preventing early development of defects having a negative impact on traffic safety. The main purpose in applying innovative technologies in transport structures deals with traffic safety improvement.

Approaches to ensuring traffic safety for persons with reduced mobility

Abstract This article is dedicated to one of the major problems in many developed and developing countries: how to ensure traffic safety for persons with reduced mobility (PRM). Nowadays, this population group is given special attention. For example, Russia has a large number of targeted programs aimed at improving the quality of their lives and, in particular, their safe use of the transport infrastructure in many cities. The paper presents an analysis of this population group and a statistical overview of its distribution in the urban environment. Using the example of the Belgorod agglomeration, the main areas hindering their proper use by persons with reduced mobility are identified. To improve traffic safety and reduce social tension, a non-governmental organization (NGO) was established that on a pro-bono basis developed a project for rearrangement and reconstruction of the main stop facilities in the Belgorod agglomeration for transportation of PRM. The expected results of NGO activity are in many ways similar to the results of targeted programs, namely, in terms of the decrease of social tension, improvement of traffic safety and, as a result, improvement of life quality in the city.

Traffic safety system management

Abstract The majority of economic activity of a country more or less depends on road transport. Road transport development has positive and negative consequences. As for negative consequences, it is largely recognized that inadequately designed transportation systems can damage the living and working environment and pose a threat to the population. The article addresses an issue of traffic safety system management. At the present time, the issue of developing an efficient transportation system with traffic safety as its main aspect remains acute. Studies show a clear correlation between the government policy and measures on traffic safety improvement. It should be noted that economic reasons for preference of such measures shall be given. The following three phases of traffic safety development are analyzed within the framework of the traffic safety system: creation, growth and consolidation. The above-mentioned phases are indicative of a correlation between the accident rate, activities in the field of traffic safety and government policy. An important stage is the determination of traffic safety problems, characterizing risk factors, which will subsequently serve as a basis for the selection of the most important traffic safety indicators. Thus, a need to manage the traffic safety system arises. Traffic safety management represents a comprehensive approach to road users, transport infrastructure and vehicles. Its successful implementation depends on sequential measures which fit into the following scheme: strategy–technology–education. Priority tasks of the national social and economic development include tasks of road users’ health and life preserving.

Method for the assessment of traffic safety criteria in regions of the Russian Federation

Abstract The article discusses results of studies of needs for the improvement of traffic safety in regions of the Russian Federation with a high level of automobilization. A comparative analysis of traffic safety assurance indicators is performed. An analysis of the accident rate, performed based on the data for the Saratov and Samara Regions, allows assessing the road accident risk and determining a dependency between the automobilization level and the accident rate. Efficiency of the implementation of measures on traffic safety improvement is determined. The risk of road accidents and fatalities is predicted.