Lane Width Research Articles

15-Year Performance of SPS-2 Project in Kansas

The Long Term Pavement Performance (LTPP) SPS-2 experiment was designed to study the structural factors, such as drainage, base type, concrete strength, thickness, and lane width for rigid pavements. The SPS-2 experiment section in Kansas, constructed in 1992, is a jointed, dowelled plain concrete pavement. The experiment consisted of twelve standard SPS-2 sections and one Kansas Department of Transportation (KDOT) supplemental/control section. These sections have been monitored by the LTPP program since construction. Performance monitoring included measurements for ride quality (International Roughness Index, IRI), faulting, cracking, and surface deflections. Performance parameters analyzed in this study included IRI, faulting, cracking (combined longitudinal and transverse crack lengths), and joint load transfer efficiency (LTE). The results show that the project has performed very well to date. Most sections are smooth, crack free, and have negligible faulting. The load transfer efficiency of the sections has been good too. The drainable sections with permeable asphalt treated base have performed the best. These sections were built smoother and remained so after 15 years of service. The section with low PCC slab thickness (203-mm) and low concrete design strength (3.8-MPa) on dense graded aggregate base has performed the worst. The combination of high slab thickness and high concrete strength tends to mask the effect of base on pavement performance. The KDOT supplemental/control section with thick slab (305-mm) over dense graded, Portland cementtreated base has also performed very well. Statistical analysis of IRI and LTE data also supports these conclusions.

Urban Arterial Lane Width Versus Speed and Crash Rates: A Comprehensive Study of Road Safety

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.

FEM Analysis of Balanced Cantilever Bridgedeck Slab with Different Skewness

Abstract: The current explores the finite element method (FEM) analysis of balanced cantilever skew bridges under the higher loading class of IRC 6:2017. The study delves into how increased skewness of the deck impacts the structural responses. For this study, a part of bridge is taken with 14m span and 3.5m width of lane taken into account for analysis. Using different skew angles, total 7 cases have created and analysed. After analysis the checks have been performed to verify the deck slab performance. Different conclusions have been drawn on deck slab, other structural members such as pier and longitudinal girder. Findings indicate that greater skewness results in elevated stress levels, particularly in the deck slab. The analysis reveals a direct proportionality between the degree of skewness and the magnitude of stress observed, underscoring the significance of skew angle in structural performance assessments

Research on the possibility of carrying out convoy driving missions using vehicles with varying degrees of autonomy

The objective of this work is to assess the possibility of driving unmanned vehicles in a convoy, depending on the vehicle type (wheeled or tracked, level 0, according to SAE J3016), and the mutual coincidence with a human-controlled vehicle in accordance with the driving scenario adopted. The assessment is based on tests carried out while driving the vehicles along a designated route and measuring the physical quantities that describe the vehicles’ motion, such as the components of the velocity vectors and distances between the vehicles. The tests were carried out on a safe training ground, using inertial-satellite devices mounted on the vehicles; they provide a good basis for planning the minimum passage corridor for a column of vehicles. During the tests, the expected distances between the vehicles were recorded and analyzed depending on the above-mentioned types of the vehicles; based on that, the possibility of using the technology in the carrying out of various missions for the needs of the tactical level units of the Polish Armed Forces was preliminarily assessed. The required lane width for the safe passage of Target 1, Hunter and Target 2 vehicles along the designated routes was calculated, taking into account the external dimensions of the vehicles, the additional widths associated with the vehicles' yaw angles and the maximum lateral distances between the vehicles. During tests of a convoy of remote-controlled vehicles, maintaining a speed of 1.5 m/s and a distance of 10 m, the requirements for the lane width for safe passage were analyzed. The largest lateral gaps were observed between Target 2 and Hunter vehicles, which may affect the planning of the convoy route. The differences in lane width between the two tests were due to the yaw angles of the vehicles and their different dimensions and drive types. In the first test, the lane width for Target 1 and Hunter was 5.50 m and for Target 2 3.70 m; in the second test it was reduced to 3.73 m and increased to 3.75 m, respectively.

A spatial-statistical model to analyse historical rutting data

ABSTRACT Pavement rutting poses a significant challenge in flexible pavements, necessitating costly asphalt resurfacing. To address this issue comprehensively, we propose an advanced Bayesian hierarchical framework of latent Gaussian models with spatial components. Our model provides a thorough diagnostic analysis, pinpointing areas exhibiting unexpectedly high rutting rates. Incorporating spatial and random components, and important explanatory variables like annual average daily traffic (traffic intensity), asphalt type, rut depth and lane width, our proposed models account for and estimate the influence of these variables on rutting. This approach not only quantifies uncertainties and discerns locations at the highest risk of requiring maintenance, but also uncover spatial dependencies in rutting (millimetre/year). We apply our models to a data set spanning eleven years (2010–2020). Our findings emphasise the systematic unexplained spatial rutting effect, where some of the rutting variability is accounted for by spatial components, asphalt type, in conjunction with traffic intensity, is also found to be the primary driver of rutting. Furthermore, the spatial dependencies uncovered reveal road sections experiencing more than 1 millimeter of rutting beyond annual expectations. This leads to a halving of the expected pavement lifespan in these areas. Our study offers valuable insights, presenting maps indicating expected rutting, and identifying locations with accelerated rutting rates, resulting in a reduction in pavement life expectancy of at least 10 years.

Deck Slab Skewness Behavior on Pier and Longitudinal Girder of Balanced Cantilever Bridge: An Analytical Study

The finite element method (FEM) analysis of balanced cantilever skew bridges under the higher loading class of IRC 6:2017 is explored in this study. The impact of increased skewness in the deck on other structural members of the bridge is examined. For the analysis, a portion of a bridge with a span of 14 meters and a lane width of 3.5 meters is considered. Seven cases are created and analyzed using various skew angles. After the analysis, checks are performed to evaluate how the performance of the deck slab influences other bridge components, including the longitudinal girder. Conclusions are drawn regarding the pier and longitudinal girder based on the results. It is found that greater skewness in the deck slab leads to increased values of parameters such as axial forces, shear forces, bending moments, and torsional moments in the bridge. The analysis demonstrates a direct proportionality between the skew angle and the magnitude of stress, highlighting the critical role of skewness in structural performance evaluations.

Trajectory Planning and Tracking Control for Single Lane Changing with Different Driving Styles of Intelligent Vehicles Based on Seventh-Degree Polynomial

<div>Single lane changing is one of the typical scenarios in vehicle driving. Planning an appropriate lane change trajectory is crucial in autonomous and semi-autonomous vehicle research. Existing polynomial trajectory planning mostly uses cubic or quintic polynomials, neglecting the lateral jerk constraints during lane changes. This study uses seventh-degree polynomials for lane change trajectory planning by considering the vehicle lateral jerk constraints. Simulation results show that the utilization of the seventh-degree method results in a 41% reduction in jerk compared to the fifth-degree polynomial. Furthermore, this study also proposes lane change trajectory schemes that can cater to different driving styles (e.g., safety, efficiency, comfort, and balanced performance). Depending on the driving style, the planned lane change trajectory ensures that the vehicle achieves optimal performance in one or more aspects during the lane change process. For example, with the trajectory that provides the best comprehensive performance under given constraints (initial speed of 20 m/s, lane width of 3.5 m, and a longitudinal distance of 50 m to the obstacle in front), the four-wheel steering model predictive control can effectively track the planned trajectory, with the maximum jerk value being 6.4 m/s<sup>3</sup> and the longitudinal speed after lane change being approximately 12.6 m/s. Although this study assumes specific longitudinal displacement before and after the lane change, the methodology is applicable to other scenarios. For example, it can determine the shortest longitudinal displacement and the optimal lane change trajectory given predefined vehicle speeds and maximum lateral acceleration conditions. The lane change trajectories developed in this study can be directly applied to the system design of autonomous vehicles.</div>

Arborização urbana não planejada como barreira à acessibilidade

Urban afforestation, when well planned, brings several benefits to cities and citizens. However, when poorly planned, it can generate several economic and socio-environmental problems, such as those that hinder and/or limit people's mobility and access to various public facilities. In this sense, the objective of this study was to evaluate the impacts of urban trees from the perspective of accessibility on the sidewalks of Avenida Lomanto Júnior, Jequié - BA, with NBR 9050/2020 being used as a parameter to evaluate the conditions of this road. Although a good part of this Avenue meets the general dimensions required, several nonconformities were observed regarding the width of the free lanes, signaling, flooring and the presence of obstacles. In several stretches, it was possible to observe the presence of trees that limit or prevent the movement of people with some type of disability or reduced mobility. Thus, considering mobility as a constitutional right, the elaboration of a project and the implementation of actions that guarantee citizenship and accessibility to all people, without any kind of distinction, are essential.

A multi-scale user-friendliness evaluation approach on cycling network utilizing multi-source data

Cycling is a promising solution to transportation decarbonization and urban sustainability. To enhance the cycling environment, it's essential to assess the user-friendliness of cycling networks. Existing related studies lack large-scale quantitative assessments and typically focus on segments, which are cost-ineffective for extensive spatial coverage and disregard the comprehensive impact of the cycling network system. Therefore, we propose a multi-scale user-friendliness evaluation approach for cycling networks utilizing multi-source geospatial data. First, we construct the cycling network using bike-sharing trajectory data. Then, to assess the user-friendliness of individual cycling segments as transportation spaces, we derive and evaluate six fine-grained quantitative indicators of bike lanes (separation, shade, width, pavement, slope undulation, and connectivity) from streetview images, DEM, and the aforementioned cycling topological network. Thirdly, cycling communities, representing inhabitants' daily living spaces, are detected based on trajectory density that informs cycling patterns, and their user-friendliness is evaluated by combining the performance of cycling segments with the spatial distribution of POI facilities within each community. An empirical study in Xiamen, China demonstrates the effectiveness of the proposed method in pinpointing specific indicators at particular segments/underdeveloped communities, thus guiding investment and optimization of cycling infrastructure to promote greater adoption of cycling as a mode of transportation.

What turns a bicycle street into a street for cyclists? A multimodal study on subjective safety of infrastructure measures on bicycle streets using an approach in virtual reality

In an increasingly urban and sustainable transportation-focused world, cycling emerges as a key environmentally friendly and health-promoting mode of travel. This paper addresses the gap in understanding cyclists' subjective safety, particularly in relation to bicycle streets in Germany. Utilizing a multimodal approach, two studies were conducted: an online questionnaire (Study I) and a Virtual Reality (VR) evaluation (Study II), focusing on the Reichenhainer Straße in Chemnitz. Study I involved N = 182 participants who regularly used the bicycle street. The questionnaire covered various aspects including mobility behavior, cycling experience, and subjective safety, using a 6-point Likert scale. Infrastructure characteristics were represented through images. Results showed that participants generally felt safe on the bicycle street, with key factors being the lane width and restrictions on motorized traffic. Study II, a pioneering effort in using VR and stereoscopic 360° images for evaluating cycling infrastructure safety, involved N = 32 participants. It provided a realistic evaluation of infrastructure elements and their impact on perceived safety. The study revealed significant differences in safety ratings based on the presence of cars and cyclists' experience levels. The use of VR allowed for a focused examination of infrastructure characteristics and their perceived safety, highlighting potential areas for improvement. Both studies demonstrated consistent results, underscoring the subjective safety of the Reichenhainer Straße, which was perceived as safer than the average bike-accessible infrastructure in Chemnitz. The VR method proved effective for detailed evaluation of subjective safety, independent of participants' familiarity with the specific infrastructure. This approach offers a structured, controlled, and resource-efficient way to evaluate cycling infrastructure under laboratory conditions. In conclusion, the findings align with existing literature and emphasize the importance of lane width and reduced motorized traffic for cyclists' safety. The innovative VR method, while still developing, offers promising implications for future citizen participation initiatives and infrastructure planning projects, enabling efficient post-completion evaluations of subjective safety. Such practices are rare in German planning offices, highlighting the paper's contribution to enhancing urban cycling infrastructure planning and safety assessment.

Study on the Deviation Characteristics of Driving Trajectories for Autonomous Vehicles and the Design of Dedicated Lane Widths

The vehicular trajectory offset represents a critical controlling element in the design of lane width. In light of the paucity of extant research on the lane widths for dedicated autonomous vehicle lanes, this study deployed the PreScan-Simulink co-simulation platform. Based on the established typical lateral and longitudinal control methods for autonomous vehicles, we initially identified the primary factors influencing trajectory offset through multifactorial coupled analysis. Subsequently, we conducted quantitative research on vehicle trajectory offset using S-shaped curves to elucidate the patterns in geometric elements’ impact on trajectory offset. Following this, we established a model of the relationship between design speed and trajectory offset under different vehicle types. Ultimately, we calculated the lane width values for scenarios involving varying positions and numbers of dedicated lanes. The results demonstrate that vehicle speed significantly impacts the trajectory offsets of autonomous vehicles. For passenger cars, the mean offset at speeds between 60 and 130 km/h is approximately 10 cm. At higher speeds of 140–150 km/h, the offset is more variable. The range of offset exhibited by trucks at speeds between 60 and 100 km/h is [8 cm, 16 cm]. In the case of a single dedicated lane, the width of the inner lanes intended for passenger cars is [2.60 m, 3.00 m], while the outer lanes designed to accommodate trucks have a width of [3.00 m, 3.20 m]. In scenarios with two dedicated lanes, the width of lanes for passenger cars can be reduced further, whereas the required lane width for trucks remains largely unchanged compared to that for single-lane setups. The conclusions show that the width of lanes adapted to autonomous vehicles could be reduced, which could help to optimize the use of road space, thus potentially reducing the occupation of land resources, reducing the environmental impact of road construction, and contributing to sustainable development. This study also provides valuable insights for the design of lanes dedicated to autonomous vehicles.

Evaluation of Selected Factors Affecting the Speed of Drivers at Signal-Controlled Intersections in Poland

In traffic engineering, vehicle speed is a critical determinant of both the risk and severity of road crashes, a fact that holds particularly important for signalized intersections. Accurately selecting vehicle speeds is crucial not only for minimizing accident risks but also for ensuring the proper calculation of intergreen times, which directly influences the efficiency and safety of traffic flow. Traditionally, the design of signal programs relies on fixed speed parameters, such as the posted speed limit or the operational speed, typically represented by the 85th percentile speed from speed distribution data. Furthermore, many design guidelines allow for the selection of these critical speed values based on the designer’s own experience. However, such practices may lead to discrepancies in intergreen time calculations, potentially compromising safety and efficiency at intersections. Our research underscores the substantial variability in the speeds of passenger vehicles traveling intersections under free-flow conditions. This study encompassed numerous intersections with the highest number of accidents, using unmanned aerial vehicles to conduct surveys in three Polish cities: Toruń, Bydgoszcz, and Warsaw. The captured video footage of vehicle movements at predetermined measurement sections was analyzed to find appropriate speeds for various travel maneuvers through these sections, encompassing straight-through, left-turn, and right-turn relations. Our analysis focused on how specific infrastructure-related factors influence driver behavior. The following were evaluated: intersection type, traffic organization, approach lane width, number of lanes, longitudinal road gradient, trams or pedestrian or bicycle crossing presence, and even roadside obstacles such as buildings, barriers or trees, and others. The results reveal that these factors significantly affect drivers’ speed choices, particularly in turning maneuvers. Furthermore, it was observed that the average speeds chosen by drivers at signalized intersections did not reach the permissible speed limit of 50 km/h as established in typical Polish urban areas. A key outcome of our analysis is the recommendation for a more precise speed model that contributes to the design of signal programs, enhancing road safety, and aligning with sustainable transport development policies. Based on our statistical analyses, we propose adopting a more sophisticated model to determine actual vehicle speeds more accurately. It was proved that, using the developed model, the results of calculating the intergreen times are statistically significantly higher. This recommendation is particularly pertinent to the design of signal programs. Furthermore, by improving speed accuracy values in intergreen calculation models with a clear impact on increasing road safety, we anticipate reductions in operational costs for the transportation system, which will contribute to both economic and environmental goals.

Determinants of cyclists' willingness to comply with mixed traffic provision and to ride on the carriageway rather than the pavement

Stakeholders in many municipalities worldwide are committed to promoting cycling and improving cycling provision. Scarcity of space is a major issue in most of these cities, particularly for main streets with significant movement and place functions. Multiple demands exist on these streets, including moving pedestrians, cyclists, motorised vehicles, parking, people waiting at public transport stops, or staying in the street for place activities. Mixing cyclists and motorised vehicles in the same space in the carriageway might be the only possible solution for cycling provision in these contexts, which is applied in many German cities. The aim of this study is to evaluate the acceptance of cycling in mixed traffic, which we measure as the proportion of cyclists riding on the carriageway versus on the pavement. The empirical work in this study is based on video observations at 273 study sites with a total length of 124 km located in 13 cities in Germany. 260 of these study sites have no marking for cyclists, and 13 have bicycle pictograms. A total of 34 874 cyclists are recorded at these study sites. A logistic regression model is used to quantify the effect of exposure and infrastructure characteristics on the proportion of cyclists on the carriageway. Volumes of motorised vehicles, lane widths > 3.00 m and city type show a significant negative effect on the acceptance of cycling on the carriageway. Cyclist volumes, bicycle pictograms, and a speed limit < 50 km/h significantly increase the likelihood of cycling on the carriageway. The model is then applied to develop evidence-based recommendations on appropriate conditions for mixed traffic provision for cyclists, ensuring pre-defined levels of acceptability. Cycling in mixed traffic without bicycle pictograms should only be recommended with traffic volumes of a maximum of 400 vehicles per hour and a speed limit of < 50 km/h to achieve a proportion of cyclists on the carriageway of 90%. The marking of bicycle pictograms increases acceptance.

The Influence of Vehicles Parking on the Roadside as Reduction of Lane Width on Traffic Performance

The city of Poso is experiencing rapid economic growth, attracting many newcomers and developing various commercial facilities along its streets. This study analyzes traffic performance on three road sections in Poso City: Jl. Pulau Irian Jaya (District Road), Jl. Pulau Sumatera (National Road), and Jl. Kasintuwu (Provincial Road), focusing on the impact of on-street parking as a side friction and lane width reduction on road capacity and degree of saturation (DS). The methods used are MKJI 1997 and PKJI 2023. The study results indicate that road capacity decreases and DS increases significantly when using the PKJI 2023 method compared to MKJI 1997. Jl. Pulau Irian Jaya experienced an increase in DS from 0.372 to 0.410 (side friction) and from 0.874 to 0.94 (lane width reduction). Jl. Pulau Sumatera showed an increase in DS from 0.716 to 0.776 (side friction) and from 0.75 to 0.84 (lane width reduction). Meanwhile, Jl. Kasintuwu showed an increase in DS from 0.114 to 0.118 (side friction) and from 0.20 to 0.21 (lane width reduction). These results suggest that the PKJI 2023 method provides a more conservative estimate, indicating a more significant decline in traffic performance compared to MKJI 1997.

Interactive effects analysis of road, traffic, and weather characteristics on shared e-bike speeding risk: A data-driven approach

As electric bikes (e-bikes) rapidly develop in China, their traffic safety issues are becoming increasingly prominent. Accurately detecting risky riding behaviors and conducting mechanism analysis on the multiple risk factors are crucial in formulating and implementing precise management policies. The emergence of shared e-bikes and the advancements in interpretable machine learning present new opportunities for accurately analyzing the determinants of risky riding behaviors. The primary objective of this study is to examine and analyze the risk factors related to speeding behavior to aid urban management agencies in crafting necessary management policies. This study utilizes a large-scale dataset of shared e-bike trajectory data to establish a framework for detecting speeding behavior. Subsequently, the extreme gradient boosting (XGBoost) model is employed to identify the level of speeding risk by leveraging its excellent identification ability. Moreover, based on measuring the degree of interaction among road, traffic, and weather characteristics, the investigation of the complex interactive effects of these risk factors on high-risk speeding is conducted using bivariate partial dependence plots (PDP) by its superior parsing ability. Feature importance analysis results indicate that the top five ranked variables that significantly affect the identified results of speed risk levels are land use density, rainfall, road level, curbside parking density, and bike lane width. The interaction analysis results indicate that higher levels of road and bike lane width correspond to an increased possibility of high-risk speeding among riders. Land use density, curbside parking density, and rainfall display a nonlinear effect on high-risk speeding. Introducing road level, bike lane width, and time interval could change the patterns of nonlinear effects in land use density, curbside parking density, and rainfall. Finally, several policy recommendations are proposed to improve e-bike traffic safety by utilizing the extracted feature values associated with a higher probability of high-risk speeding.

Selective State DOT Lane Width Standards and Guidelines to Reduce Speeds and Improve Safety

This research investigates the lane width standards and guidelines implemented by various State Departments of Transportation (DOTs) to reduce vehicle speeds and enhance road safety. Lane width reduction is often perceived as a strategy to mitigate speed and improve safety. Still, its effectiveness and implications vary across different contexts, including regions, urban/rural settings, or other geometric design features. Drawing from interviews with five State DOTs and a review of their road design manuals, this study aims to identify suggested lane widths depending on the contexts, design exception process when narrowing or widening lane widths, and introduce representative before/after studies. The findings indicate that State DOTs tend to have lower recommended lane widths in urban areas than in rural areas. Moreover, lane width standards among these states vary due to several factors, including the geographical location of roadways (urban or rural areas), design or posted speeds, traffic volume, road classification, and geometric road design features. Design exceptions are required if the existing or proposed design element is incompatible with both AASHTO and department governing criteria. In conclusion, the findings will provide valuable insights and recommendations for policymakers, transportation planners, and road engineers to inform optimal lane width and decision-making processes.

Contribution of congested traffic flow condition to air pollution at intersections in Addis Ababa, Ethiopia

Currently, one of the serious problems in the world is transport-related air pollution. Air pollution from vehicles was not considered properly in the plan, design, and management system of the roads in Addis Ababa city, to solve the problem of traffic congestion. It is influenced by different factors such as road geometry, road surface type, traffic congestion, traffic characteristics, fuel type, and meteorological parameters. This study was aimed to investigate the contribution of congested traffic flow conditions on air pollution at intersection points in Addis Ababa city. To carry out the study, seven intersection points were selected in the city randomly. For the measurement technique of carbon monoxide (CO) and sulfur dioxide (SO2) gases, a portable Aeroqual series 500 instrument was exercised, and for the particular matter (PM2.5 and PM10), Light Amplification by Stimulated Emission of Radiation (LASER) was adapted. To count the number of traffic on the site, a video camera method was utilized. For the data analysis techniques, a multiple linear regression method was practiced, which is very powerful for multiple independent variables with a single dependent one. The study revealed that the level of traffic congestion at each selected intersection is at a severe level. During the congested time, as a base of the steady condition, the pollutants concentration of CO, SO2, PM2.5, and PM10 were increased by an average of 19.10, 51.61, 33.83, and 29.07 % respectively. Based on the analyzed results, when the concentration of pollutants increases, the traffic volume, percentage of heavy vehicles, green time, and approach grade are also increased. On the other hand, the concentration of pollutants decreased when the lane width and wind speed increased. Therefore, any concerned bodies in and around Addis Ababa city should take remedial measures to decrease the emission of the concentration of the pollutants. This investigation is very important for policymakers, municipalities, and planners to do any activities in the city. Researchers can also use it as a reference, for further investigations and remedial measurements.

Developing Safety Performance Functions for Severe Distraction-Related Crashes along Kentucky’s Rural and Urban Two-Lane Roadways

This study develops safety performance functions (SPFs) for severe (“KA” or “fatal and suspected serious injury”) distraction-related crashes along Kentucky’s rural and urban two-lane undivided roadway segments using recent four-year (2018–2021) crash records. Additional efforts were made to meticulously scrutinize crash narratives categorized as non-distracted and correct those cases. To account for crash under-dispersion, the Conway–Maxwell–Poisson, heterogeneous Conway–Maxwell–Poisson, zero-inflated Conway–Maxwell–Poisson, and zero-inflated heterogeneous Conway–Maxwell–Poisson (ZI-HTCMP) models were fitted and compared. The ZI-HTCMP model outperformed the other models with respect to several goodness-of-fit measures (e.g., mean absolute deviance and mean square prediction error). From the developed SPFs for rural and urban two-lane roads, wider lanes and higher speed limits (55 mph) were associated with increased severe distraction-related crash frequencies. Furthermore, some variables were found to be significant in rural areas, but insignificant in urban areas, and vice versa. For example, major collector roads, minor collector/local roads, the presence of roadside guardrails, wider right-hand shoulders, the presence of horizontal curves, and the presence of vertical grades were associated with increased crash frequencies along rural two-lane roads. In addition, the proportion of heavy vehicles (>5%) and the existence of paved shoulders were associated with increased crashes along urban two-lane roads. The empirical Bayes method was then used to rank the top 10 distraction-related high crash locations (HCLs) for both rural and urban two-lane segments. In-depth investigation of HCLs highlighted single-vehicle distraction-related crashes as the most common collision type. Countermeasures were proposed to help reduce severe distraction-related crashes, for example, installing chevron signs along rural two-lane roads.

Methods for Selecting Linguistic Variables in the Fuzzy Traffi c Light Control System

To increase the capacity of the intersection and simultaneously reduce the travel time of the vehicle, optimization of traffic light control is necessary. The existing traffic light control systems cannot control dynamic systems in which several factors influence the decision-making process. The determination of factors (output variables) and the fuzzification process are the main problem of the fuzzy logic algorithm, and the quality of the compilation of the term set of input linguisticvariables and the definition of the function of belonging affect the optimal control of the light signals. The article provides an analytical overview of the ways of using linguistic variables for fuzzy inference systems when controlling traffic light signals. The subject of the article is the input linguistic variables for decision-making in a fuzzy management model. The analysis of modern research is presented and the main input linguistic variables are described. In the first section of the work, the general principle of building a rule base for fuzzy inference systems based on the Mamdani and Takagi-Sugeno methods is considered. The following sections are devoted to the peculiarities of such output linguistic variables that affect the operation of a fuzzy traffic light, such as: the number of vehicles, the current time of the green signal, road users (pedestrians), weather conditions and the number of lanes (width) of intersected roads. Accounting for these variables, their fuzzification and the formation of an appropriate rule base for the design of fuzzy systems is a very difficult task. In this regard, one of the key problems is precisely the problem of choosing the necessary input parameters depending on the type of intersection.A review of the literature has shown that the research of the fuzzy controller in traffic management is still at the initial stage of development. Many of the unresolved issues raised in ozor can be addressed in further research

Influence of Driver Eye Height and Obstacle Height on Sight Distance

Abstract Road traffic safety is a series of methods and measures aimed to reducing the risk of injury for road users. Road accidents are events that have an extremely strong socio-economic impact on society as a whole and directly on its members. The road is a basic component of the road safety system and is represented by the road and the area adjacent to it, which influences the flow of road traffic. Basically, the driver “reads” the road and based on that information adopts the behaviour, mainly speed. The road elements of the road and the homogeneity of these characteristics, visibility in curves, the layout of intersections, the uniformity and roughness of the road surface are only some of the essential elements of the traffic safety study at the design stage. But even on a very well-designed road, many accidents occur because of the other possible factors. The road elements characteristic of roads are the totality of the road components in plan view, elevation and cross section. In this case study, a section of road of technical class III was considered. The design speed of the road section studied is 80 km/h and the lane width is 3.50 m, according to the technical standards in force. The study was carried out for design speeds of 80 km/h and 60 km/h respectively, the height of the eyes will be considered as 1.00 m, 1.10 m, 1.20 m and 1.30 m, and for the height of the obstacle will have variable height, more precisely, for the speed of 80 km/h the heights will be 0.20 m, 0.40 m, 0.60 m, 0.80 m, 1.00 m, and for the speed of 60 km/h, they will be 0.00 m, 0.10 m, 0.20 m.