A Decision Support System for Road Safety Analysis

This research paper examines the application of artificial intelligence (AI) in road network inventory and network-wide road safety assessment. An overview of current research related to this field is presented and various aspects of the use of AI in road infrastructure and safety assessment are analysed. In today’s world, where the road network continues to develop and grow, the use of AI can offer significant advantages in the inventory and assessment of road infrastructure and safety. AI can be used to process large volumes of data collected from various sources such as geographic data, photos, documentation and more. One of the main aspects that the article looks at is the use of AI to automatically process data and create a digital inventory of the road network. AI systems can analyse geographic data and photos to identify and classify roads, road signs, markings, and other elements of road infrastructure. This can facilitate engineers and competent authorities in the process of road inventory and maintenance. Another important aspect discussed in the paper is the use of AI for the general assessment of road safety. AI models can analyse road infrastructure inventory data, as well as traffic data, crashes, and other factors, to provide a comprehensive assessment of road network safety. This allows the competent authorities to identify vulnerable places, carry out preventive measures and plan appropriate interventions aimed at improving road safety. In conclusion, the paper highlights the possibilities and advantages of using artificial intelligence in road network inventory and network-wide road safety assessment. Such an approach can contribute to more efficient management of road infrastructure and improvement of road safety.

ABSTRACTLane and shoulder widths are important highway safety factors because wider lanes and shoulders generally help to reduce crashes. In practice however, due to physical limitations of the right-of-way or statutory restrictions, it may be the case that the existing overall width of the roadway (lanes plus shoulders) cannot exceed a certain value. For a given overall roadway width constraint, wider lanes mean there will be smaller space for shoulders, and vice versa. In such zero-sum situations, it is not certain if a cross-sectional configuration with wide lanes and narrow shoulders is safer compared with one with narrow lanes and wide shoulders. Clearly, for a given total roadway width (TRW), the trade-off between shoulder and lane widths should be evaluated in order to maximize the user benefits (safety) without unduly incurring excessive agency life-cycle costs of construction and preservation. The TRW allocations to the lane and shoulder, expressed as the ratio of lane width to shoulder width, will generally depend on the TRW; lane and shoulder pavement material types and costs; and traffic volume, among other factors. In order to optimize the lane and shoulder width allocations for a given TRW, this paper proposes a framework that formulates the problem as an optimization problem with the objective of minimizing the total (agency and user) life-cycle cost of the roadway. First, the relationships are established between lane/shoulder widths and the resulting user costs (crashes), and also between lane/shoulder widths and the associated agency costs of lane/shoulder construction and preservation. The sensitivity of the optimal solution to different evaluation inputs (such as the relative weights between the agency and user costs) is also analyzed. Using the developed framework, the paper presents a number of decision support charts that can be used by highway agencies to determine the optimal lane and shoulder widths under a given set of conditions including the highway functional class and the total available roadway width. The flexibility of the proposed optimization framework to accommodate risk compensation effects was also demonstrated.

Crashes in road curves contribute significantly to road traffic fatalities in developing countries. The crash risks increase when there are multiple vertical and horizontal curves on the road section. In this study, we diagnose the crash-contributing factors along the crash-prone and curvy Odumasi-Oterkpolu road in Ghana and propose countermeasures. Spot speed counts were done using radar guns in addition to manual traffic counts, field inspections, and victim self-reports. Secondary police crash data (from 2015 to 2019) were collected from the Building and Road Research Institute of Ghana. Multiple regression and descriptive analyses were computed to identify crash-contributing factors. Vehicle brake failure and driver inattention were identified as the main driving errors that contribute to crashes in the road curves. Notably, the majority of crashes involved movements in left-turning lanes, in other words towards drivers’ left sides. Speed, traffic volume, and the volume of motorcycles and medium trucks had the strongest association with fatalities. Overall, the road lacks street lights, guardrails, road signs, road markings, posted speed limits, and durable pavement. This is the first empirical investigation of the studied road; therefore, the findings and proposed countermeasures will help to improve road design and safety measures.

In Indonesia, traffic accidents occur on 23.55% of national roads and 75.08% of rural roads. The rural roads were identified as accident-prone areas. As a result, unsafe roads hinder population mobility, disrupt daily life, and reduce access to education, employment, and essential services, thereby affecting the well-being and development of rural communities. To identify the dominant factors that influence the frequency of collisions, a more thorough analysis of the multifactorial causes of traffic accidents in accident-prone areas is necessary. This study focused on analyzing the factors that contribute to road traffic accidents. Cross-tabulation was done using chi-square analysis. The chisquare test does not assume a normal distribution of data, which is beneficial when dealing with real-world data that may not follow normal distribution patterns. This flexibility makes it a robust choice for analyzing traffic accident data, which can be highly variable and not normally distributed. The results of the chi-square analysis for significance values below 0.05 indicate that there is a correlation between accident-causing factors (the independent variable) and collision frequency (the dependent variable). The results indicate that human factors, such as carelessness and high speed, as well as road and environmental factors, such as horizontal alignment, road width, clear zone, road signs, road markings, and land use, influence traffic accidents. Infrastructure factors such as horizontal alignment, road width, clear zones, shoulders, signs, and markings influence traffic accidents because they directly impact road user safety. Non-standard road geometry (horizontal alignment, road width, shoulder width, and clear zone) combined with incomplete road safety facilities (signs and markings) have the potential to cause traffic accidents. Therefore, harmonizing road geometry and equipment is necessary to improve arterial road safety, especially in accident-prone areas. Furthermore, speed management across a variety of land uses is required to reduce traffic accidents.

Data Envelopment Analysis for the assessment of road safety in urban road networks: A comparative study using CCR and BCC models

Reducing vehicle lane widths has been proposed as an effective strategy to decrease vehicle speeds and enhance road safety. However, the safety benefits of narrower travel lanes remain a topic of debate due to mixed findings in the literature. This study examines the relationship between lane width, vehicle speed, and crash occurrence to comprehensively understand their impact on road safety and transportation planning. Using data from 320 urban arterial sections in Utah, the analysis reveals that narrower lane widths are associated with reduced vehicle speeds. For every additional foot of lane width, 85th and 95th percentile speeds increase by 1.012 mph and 1.088 mph, respectively. Furthermore, injury crash modeling indicates that a one-foot increase in lane width is associated with a 38.3% increase in the odds of an injury crash on a roadway section. These findings contribute to the growing evidence supporting the implementation of narrower lane widths as a strategy to improve road safety, foster multimodal infrastructure, and promote sustainable urban transportation systems. We recommend that UDOT adopt a minimum lane width of 10 or 11 feet for arterials in highly urbanized areas, such as downtowns and major activity centers.

Horizontal road marking along with road signs is an essential factor that ensures road safety. The quality of road markings largely depends on the quality of the application. In today’s, for road marking are used road marking machines. They are complex high-performance automated units requiring highly professional operators. Stink to classify for the way of marking, design of the running gear, base machine, type of drive, productivity and the most important signs. The article describes the principles of the operation of marking machines and the main technical characteristics of machines from leading manufacturers: GRACO, SТiM, Hofmann. When applying road marking, special attention should be paid to the use of certified materials and certified equipment. The results of measuring the geometric and lighting indicators of horizontal road marking are presented. During certification, marking is applied with a marking machine. During the application, the thickness of the liquid paint layer is determined by a calibrated comb. To control the lighting technical characteristics of road marking – whiteness, retroreflectivity (Rl) and brightness (Qd) coefficients, a ZRM 1021 reflectometer and a ZRM 1013 retroreflectometer are used. Geometric indicators were measured with a tape measure. The table of certification results of the Line Lazer IV 3900 machine is shown. Similar indicators were obtained during certification of the machines of Hofmann, Combizet Gruen, RoadLazer, etc. Deviations from the road marking indicators declared by the manufacturer are not observed for 3 years. All marking performed by verified marking machines meets the requirements of current regulations. Keywords: certification of machines, durability of marking, retroreflectivity, accuracy of application, brightness.

Speed choice is strongly influenced by geometric road features. In this work, the influence of lane and shoulder widths on free-flow speed was studied with the driving simulator DriS at the University of Porto in Porto, Portugal. To evaluate how speed was influenced by the cross section, this study investigated the possible influence of the order of magnitude of the practiced speeds on the effects of variations in lane and shoulder widths. Two types of roads with different base speeds were considered. The roads were presented to drivers on a driving simulator. The validity of the data obtained in the simulator was confirmed through a comparative analysis of the registered speeds in the real environments for the equivalent simulator conditions at six points of control. The lane and shoulder widths from which the free-flow speed was no longer conditioned by the dimensions of the road's cross section were obtained, as well as the reduction in speed associated with smaller widths. Contrary to what was suggested by the Highway Capacity Manual 2010, the individual effects of variations in lane and shoulder widths were not cumulative; greater impacts on free-flow speed were obtained by their simultaneous variation.

There is a need to better understand and quantify the safety implications of geometric improvements and countermeasures. A commonly accepted measure of safety effectiveness is the crash modification (CMF) defined as the expected number of crashes with a countermeasure divided by the number expected without the countermeasure. This paper evaluates the use of a case-control design to directly estimate the safety effectiveness of lane and shoulder width using the odds ratio: the probability of a crash with the countermeasure divided by the probability of a crash without a countermeasure. The case-control design is well established in epidemiology where it is used to relate factors within a study population to a particular or disease. In the highway safety context, the outcome is defined as a crash, the risk factor is a particular geometric feature or countermeasure and the subjects are roadway segments. This paper describes the of an experiment in which commonly available crash, roadway and traffic data are used to estimate odds ratios which are compared to CMFs from the literature. The comparison of these slightly different effectiveness measures are intended as a test of the efficacy of the case-control method in safety effectiveness evaluation. Geometric, traffic and crash data were obtained for more than 28,000 rural two-lane undivided highway segments in Pennsylvania for years 1997 to 2001 inclusive. A matched case-control design is developed to estimate the safety effectiveness of different lane and shoulder widths while adjusting for the confounding variables: speed limit, average daily traffic and segment length. Conditional logistic regression models are developed to estimate the odds ratio for lane and shoulder width separately. Lane and shoulder width odds ratios compare favorably to CMFs from the literature and have the additional advantage of including confidence intervals on the estimates. The paper concludes with a discussion of strengths and weaknesses of the method and recommendations for future research.

Road accidents are a major public health concern in Bangladesh, causing significant harm to individuals and society as a whole. Despite various initiatives taken by the government, the number of road accidents continues to increase, highlighting the need for a legal approach to address this issue. This study aims to analyze the current legal framework in Bangladesh with regards to road safety and identify potential areas for improvement. The study found that the current legal framework in Bangladesh contains several provisions aimed at promoting road safety, including the Bangladesh Road Transport Act, the Bangladesh Road Transport Corporation Act, and the Bangladesh Road Transport Authority Act. However, these laws lack effective enforcement mechanisms, and there is limited accountability for those who violate traffic rules. This has led to widespread flouting of traffic regulations and a high incidence of road accidents. The study recommends the introduction of stricter penalties for those who violate traffic rules, including fines and imprisonment. It also suggests the establishment of an independent road safety commission to monitor compliance with traffic rules and to ensure effective implementation of road safety measures. The commission should have the authority to investigate road accidents and to take appropriate actions against those found responsible persons. Additionally, the study recommends the introduction of mandatory training programs for all drivers and the provision of better infrastructure and technology to support road safety. This may include the installation of traffic lights and speed cameras, as well as the use of innovative technologies such as GPS-based monitoring systems. In conclusion, a legal approach is crucial in addressing the problem of road accidents in Bangladesh. By introducing stricter penalties, establishing an independent road safety commission, and investing in road safety infrastructure and technology, the government can help to reduce the number of road accidents and save lives. Further research is needed to understand the impact of these measures and to identify additional ways to promote road safety in Bangladesh.

A traffic accident is an event that cannot be avoided, an event where a motorized or non-motorized vehicle comes into contact with each other and causes both material and non-material losses and loss of life. Some of the factors that have the potential to cause accidents are the indiscipline factor in using the vehicle and disobeying existing traffic signs. Jalan Raya Bukittinggi-Payakumnbuh is a class III collector road with a width of ± 9 meters with a sidewalk. Along the audited road are shops and Ford De Kock University. This contributes greatly to attracting the number of people traveling and the high volume of vehicles crossing the Bukittinggi-Payakumbuh highway. Therefore, research was carried out starting from STA 0+100 – STA 1+500, this study aims to analyze road safety by using inspections with the AKJ (Road Safety Audit) checklist table with Y/N answers, such as general condition items, alignment roads, intersections, turning lanes, street lighting and road signs and markings. From the results obtained, the stopping sight distance for an operational speed of 50.07 km/sec in the calculation of the stopping sight distance, the distance of 52.88 meters is still below the design standard and for the ready sight distance of 161.45 meters, the maximum viewing distance of the plan is 350 meters. Based on the AKJ table (road safety audit) for the Bukittinggi-Payakumbuh highway, the highest feasible is from the aspect of signs and road markings of 68.75%, the lowest feasible value is general condition of 50%. The driver factor is the factor causing the highest traffic accidents, namely 26 accidents out of 38 accidents (68.43%), the rest is the vehicle factor, namely 12 accidents out of 38 accidents (31.57%). In order to overcome the problems on the audited roads, it is necessary to repair and complete the signs that are lacking and the maintenance of other complementary facilities in order to reduce traffic accidents. Keywords: Road safety audit, Accident, Stopping visibility, Ready visibility, Bukittinggi-Payakumbuh Highway

In the medium-term, the number of semi-autonomous vehicles is expected to rise significantly. These changes in vehicle capabilities make it necessary to analyze their interaction with road infrastructure, which has been developed for human-driven vehicles. Current systems use artificial vision, recording the oncoming road and using the center and edgeline road markings to automatically facilitate keeping the vehicle within the lane. In addition to alignment and road markings, lane width has emerged as one of the geometric parameters that might cause disengagement and therefore must be assessed. The objective of this research was to study the impact of lane width on semi-autonomous vehicle performance. The automatic lateral control of this type of vehicle was tested along 81 lanes of an urban arterial comprising diverse widths. Results showed that the semi-autonomous system tended to fail on narrow lanes. There was a maximum width below which human control was always required—referred to as the human lane width—measuring 2.5 m. A minimum width above which automatic control was always possible—the automatic lane width—was established to be 2.75 m. Finally, a lane width of 2.72 m was found to have the same probability of automatic and human lateral control, namely the critical lane width. Following a similar methodology, these parameters could be determined for other vehicles, enhancing the interaction between autonomous vehicles and road infrastructure and thus supporting rapid deployment of autonomous technology without compromising safety.

In the same road conditions and similar traffic environments, vehicle speeds vary although drivers are operating the same types of vehicles with identical performances: some of the actual speeds are higher than the design speed of the road, and some are lower. The deep reason behind this problem is this: the desired speed established by the different individuals varies. Based on the analysis of the forming process and factors influencing driver's desired speed, single-factor simulation experiments were designed, and a three-dimensional scene model was established using a virtual scene generation system. Sixteen subjects were selected to participate in the experiments, and a statistical analysis was made using the SPSS software base on experiment data. Analysis of results reveals that lane number, lane width, and shoulder width influence the desired speed; the relationship between desired speed and lane numbers, lane width, the shoulder width is respectively regressed. Finally, based on the results of the desired speed simulation experiment, an integrated model has been built, and guidelines are offered for assessing the impact of lane number, lane width, shoulder width, driver conditions and vehicle conditions, explaining how to select a correction coefficient.

Driving speed and the risk of road crashes: A review

An Impact study of highway design on casualty and non-casualty traffic accidents