Csaba Koren

56001600900

Publications - 25

Traffic Sign Detection and Quality Assessment Using YOLOv8 in Daytime and Nighttime Conditions

Csaba Koren Ziyad N. Aldoski

Publication Name: Sensors

Publication Date: 2025-02-01

Volume: 25

Issue: 4

Page Range: Unknown

Description:

Traffic safety remains a pressing global concern, with traffic signs playing a vital role in regulating and guiding drivers. However, environmental factors like lighting and weather often compromise their visibility, impacting human drivers and autonomous vehicle (AV) systems. This study addresses critical traffic sign detection (TSD) and classification (TSC) gaps by leveraging the YOLOv8 algorithm to evaluate the detection accuracy and sign quality under diverse lighting conditions. The model achieved robust performance metrics across day and night scenarios using the novel ZND dataset, comprising 16,500 labeled images sourced from the GTSRB, GitHub repositories, and real-world own photographs. Complementary retroreflectivity assessments using handheld retroreflectometers revealed correlations between the material properties of the signs and their detection performance, emphasizing the importance of the retroreflective quality, especially under night-time conditions. Additionally, video analysis highlighted the influence of sharpness, brightness, and contrast on detection rates. Human evaluations further provided insights into subjective perceptions of visibility and their relationship with algorithmic detection, underscoring areas for potential improvement. The findings emphasize the need for using various assessment methods, advanced algorithms, enhanced sign materials, and regular maintenance to improve detection reliability and road safety. This research bridges the theoretical and practical aspects of TSD, offering recommendations that could advance AV systems and inform future traffic sign design and evaluation standards.

Open Access: Yes

DOI: 10.3390/s25041027

Where Do Pedestrians Look, When Crossing Suburban Railway Lines with Right- and Left-Hand Traffic?

Gabriella Iván Csaba Koren Bayasgalan Nemekh

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2025-01-01

Volume: 1258 LNNS

Issue: Unknown

Page Range: 107-119

Description:

We have learned from childhood on, that before crossing a street, first we must look left, then to right. This is related with the right-hand traffic system of cars. The research question in this paper is: how we behave in an unfamiliar situation, when crossing left-hand traffic. In Budapest, four of the five suburban railway lines operate with right-hand traffic, but one of them works in the left-hand system. The aim of this article is to investigate the behavior of pedestrians in level crossings with right- and left-hand railway traffic and to reveal any differences between their behavior, as well as the safety of these lines. The main findings are that pedestrians look at the “built-in” left-right order, even it is not the safest option. Parallelly, accident data show worse safety situation of the line with left-hand traffic. As conclusion, some low-cost infrastructure measures are recommended.

Open Access: Yes

DOI: 10.1007/978-3-031-81799-1_11

Standardized Assessment, LiDAR-Based Measurements, and Human Perception of Traffic Signs

Csaba Koren Ziyad N. Aldoski

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2025-01-01

Volume: 1258 LNNS

Issue: Unknown

Page Range: 77-86

Description:

Traffic signs are essential informative tools for road users, with their quality regulated by international standards. Among the critical parameters for evaluation is retroreflectivity. With the rise of autonomous vehicles (AVs), new tools like LiDAR sensors and cameras have become crucial for assessing traffic signs. However, the relationship between human perception and the physical properties of these signs remains underexplored. This study compares traffic sign evaluations using retroreflectivity measurements, LiDAR data, and human assessment. Approximately 160 traffic signs were analyzed using standardized retroreflectivity measurements, with additional data collected from two different LiDAR systems mounted on an AV. Volunteers conducted human evaluations assessing visibility, legibility, and contrast with surroundings. The handheld reflectometer provided a wide range of retroreflectivity readings, while LiDAR data showed good contrast between sign faces and surroundings, though results varied between the two systems. Human assessments correlated strongly with overall appearance but showed limited correlation with the other methods. This study highlights the strengths and limitations of each evaluation approach, offering insights for improving traffic sign assessment techniques.

Open Access: Yes

DOI: 10.1007/978-3-031-81799-1_8

Improving Autonomous Vehicle Perception through Evaluating LiDAR Capabilities and Handheld Retroreflectivity Assessments

Csaba Koren Ziyad N. Aldoski

Publication Name: Sensors

Publication Date: 2024-06-01

Volume: 24

Issue: 11

Page Range: Unknown

Description:

Road safety is a serious concern worldwide, and traffic signs play a critical role in confirming road safety, particularly in the context of AVs. Therefore, there is a need for ongoing advancements in traffic sign evaluation methodologies. This paper comprehensively analyzes the relationship between traffic sign retroreflectivity and LiDAR intensity to enhance visibility and communication on road networks. Using Python 3.10 programming and statistical techniques, we thoroughly analyzed handheld retroreflectivity coefficients alongside LiDAR intensity data from two LiDAR configurations: 2LRLiDAR and 1CLiDAR systems. The study focused specifically on RA1 and RA2 traffic sign classes, exploring correlations between retroreflectivity and intensity and identifying factors that may impact their performance. Our findings reveal variations in retroreflectivity compliance rates among different sign categories and color compositions, emphasizing the necessity for targeted interventions in sign design and production processes. Additionally, we observed distinct patterns in LiDAR intensity distributions, indicating the potential of LiDAR technology for assessing sign visibility. However, the limited correlations between retroreflectivity and LiDAR intensity underscore the need for further investigation and standardization efforts. This study provides valuable insights into optimizing traffic sign effectiveness, ultimately contributing to improved road safety conditions.

Open Access: Yes

DOI: 10.3390/s24113304

Sustainability implications of lateral wander modes for autonomous trucks

Csaba Koren Richárd Nagy Mohammad Fahad

Publication Name: Discover Applied Sciences

Publication Date: 2024-03-01

Volume: 6

Issue: 3

Page Range: Unknown

Description:

Autonomous trucks can bring changes in transport infrastructure in terms of sustainability based on the type of lateral wander mode used. In this research, two lateral wander modes, a zero wander and uniform wander mode are analyzed based on their applicability for sustainability by analyzing the CO2 emissions occurred during pavements life cycle. Both lateral wander modes have been analyzed in terms of occurrence of fatigue damage by using finite element analysis in ABAQUS. The fatigue damage predictions have then been used for planning the maintenance interventions for both lateral wander modes. Life cycle analysis has been performed for the analysis period of 30 years for the pavement section of 10 km. Results show that zero wander mode generates more emissions as a result of premature fatigue damage under channelized loading. The uniform wander mode leads to 20% less emissions when compared to zero wander mode. Moreover, the use of full depth reclamation during pavement’s life cycle improves the CO2 emissions by 15% when compared to traditional removal and reconstruction methods. Therefore, the uniform wander mode is favorable for improvement of pavement sustainability in terms of CO2 emissions.

Open Access: Yes

DOI: 10.1007/s42452-024-05732-5

Finite Element Modelling of Polymer and Crumb Rubber Modifed Asphalt Mixtures

Csaba Koren Richárd Nagy Mohammad Fahada

Publication Name: Advances in Transdisciplinary Engineering

Publication Date: 2024-01-01

Volume: 59

Issue: Unknown

Page Range: 44-52

Description:

Modification of asphalt binder with crumb rubber or SBS type polymer can further enhance the viscoelastic properties of asphalt mixtures in terms of reduced permanent deformation and increased operational temperature range. In this research, the effect of different variations of crumb rubber (CR) and styrenebutadiene-styrene (SBS) consisting of Base asphalt, 4% SBS, 7% SBS, 7% CR, 15% CR and 20% have been analyzed in terms of rutting accumulation. This research is significant in terms of performance characteristics of CR and SBS modified mixtures, where based on availability and price of these modifiers, agencies can perform selection of either variations of these modifiers based on their requirement and standards in order to optimize the performance of asphalt pavements. Finite element analysis has been performed using ABAQUS, where a dual wheel having an axle load of 100 kN has been simulated with a total of 50,000 passes on a 2D model. Validated creep parameters using the Burger's model have been utilized for simulation of material decay under creep loading for each variation. Visco step loading has been used to measure rutting progression. Results show increased rutting accumulation of base asphalt among other scenarios. Furthermore, CR-20 outperforms other variations in terms of rutting accumulation. Both CR-20 and SBS7 yield the minimum rutting magnitude of 3.2 m and 3.3 mm respectively. SBS-7 leads to 39% less rutting magnitude when compared to that of base asphalt.

Open Access: Yes

DOI: 10.3233/ATDE240525

ASSESSMENT OF TRAFFIC SIGN RETROREFLECTIVITY FOR AUTONOMOUS VEHICLES: A COMPARISON BETWEEN HANDHELD RETROREFLECTOMETER AND LIDAR DATA

Csaba Koren Ziyad N. Aldoski

Publication Name: Archives of Transport

Publication Date: 2024-01-01

Volume: 70

Issue: 2

Page Range: 7-26

Description:

This study investigates the critical role of retroreflectivity in traffic signs, particularly in the context of autonomous vehicles (AVs), where accurate detection is paramount for road safety. Retroreflectivity, influencing visibility and legibility, is essential for ensuring safe road conditions. The study aims to assess traffic sign retroreflectivity using handheld retroreflectometers and LiDAR data, offering a comprehensive comparison of results with a specific focus on the RA1 and RA2 traffic sign classes. In a real-world setting, an AV equipped with LiDAR sensors, GPS units, and a stereo camera collects data on traffic signs, including point cloud attributes such as intensity and density. Simultaneously, a handheld retroreflectometer measures retroreflectivity coefficients from identified traffic signs. While retroreflectometers provide precision, they face limitations regarding time-consuming measurements and handling large or elevated signs. In contrast, LiDAR systems efficiently evaluate retroreflective features for numerous signs without such constraints. Despite both methods consistently yielding accurate retroreflectivity, the study reveals a limited correlation between LiDAR point cloud data and handheld retroreflectivity coefficients. The implications of these findings are significant, particularly in the selection and maintenance of retroreflective materials in traffic signs, with direct repercussions on overall road safety. The results offer valuable insights into leveraging LiDAR technology to enhance AVs' detection capabilities. Recommendations for further research include exploring factors influencing LiDAR intensity, establishing a more accurate relationship between intensity and retroreflectivity, correcting the point cloud during intensity calibration, and testing empirical prediction models with a larger sample size. These endeavors aim to generate a robust regression graph and determine correlation coefficients, providing a more nuanced understanding of the intricate relationship between LiDAR data and handheld retroreflectivity coefficients in the context of traffic sign assessment.

Open Access: Yes

DOI: 10.61089/aot2024.qxy24g93

Evolution of the Road Network Topology of Central European Housing Estates

Csaba Koren Attila Borsos Pál Hegyi

Publication Name: Infrastructures

Publication Date: 2023-10-01

Volume: 8

Issue: 10

Page Range: Unknown

Description:

The analysis of road network topology has attracted the attention of researchers in the past few decades. In this study, the road topology of housing estates in a few selected Central European countries (Hungary, Austria, Czech Republic, and Slovakia) was analysed. This research was carried out in three steps: (1) the road network topology of different decades from the 1950s to the 1980s was described, (2) the ratio of intersections and dead-ends was investigated, and (3) the connectivity indices were analysed and compared. The research was carried out using ESRI ArcGIS software. The results show that the design of road networks built in different countries is similar in the housing estates studied. When analysing the road networks over time, significant differences could be found in the case of Hungary for housing estates built after the 1960s. In general, connectivity has become more important, as it has gradually increased over time.

Open Access: Yes

DOI: 10.3390/infrastructures8100142

Communication between Autonomous Vehicles and Pedestrians: An Experimental Study Using Virtual Reality

Emese Makó Csaba Koren Attila Borsos Symbat Zhanguzhinova Ágoston Pál Sándor

Publication Name: Sensors

Publication Date: 2023-02-01

Volume: 23

Issue: 3

Page Range: Unknown

Description:

One of the major challenges of autonomous vehicles (AV) is their interaction with pedestrians. Unofficial interactions such as gestures, eye contact, waving, and flashing lights are very common behavioral patterns for drivers to express their intent to give priority. In our research we composed a virtual reality experiment for a pedestrian crossing in an urban environment in order to test pedestrians’ reactions on an LED light display mounted on a virtual AV. Our main research interest was to investigate whether communication patterns influence the decision making of pedestrians when crossing the road. In a VR environment, four scenarios were created with a vehicle approaching a pedestrian crossing with different speeds and displaying a special red/green sign to pedestrians. Here, 51 persons participating in the experiment had to decide when crossing is safe. Results show that the majority of people indicated they would cross in the time windows when it was actually safe to cross. Male subjects made their decision to cross slightly faster but no significant differences were found in the decision making by gender. It was found that age is not an influencing factor, either. Overall, a quick learning process was experienced proving that explicit communication patterns are self-explaining.

Open Access: Yes

DOI: 10.3390/s23031049

Lézerszkennerrel felmért közlekedési csomópontok láthatósági vizsgálata referenciasík segítségével

Csaba Koren Zsófia Magyari

Publication Name: Geodezia Es Kartografia

Publication Date: 2023-01-01

Volume: 75

Issue: 1

Page Range: 16-23

Description:

According to road design guidelines, unsignalized intersections should have certain free sight fields to ensure that vehicles approaching from different directions see each other. However, in many cases these sight fields include some obstacles which cause safety concerns. The identification of these obstacles and the planning of appropriate interventions would improve safety. In this article, we present an analysis method suitable for visibility investigation based on a laser scanner survey. We review the methods developed in recent years to select the visible and hidden points of the point cloud. Based on the presented results, we developed a procedure that is consistent with the concept of sight distance used in the field of road design. The survey was taken from an observation point of the drivers on the minor road and the sightlines were projected onto a reference plane along the major road, considering the required sight distance. The projected results appeared as "shadows" from the visibility obstacles on the reference plane. The visibility difficulties detected can be used to decide the appropriate actions to improve the safety of the intersection.

Open Access: Yes

DOI: 10.30921/GK.75.2023.1.2

Pavement Sustainability Implications of Different Lateral Wander Modes for Autonomous Trucks

Csaba Koren Richárd Nagy Mohammad Fahad

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 631-636

Description:

Autonomous trucks can bring changes in transport infrastructure in terms of sustainability based on the type of lateral wander mode used. In this research, two lateral wander modes, a zero wander and a uniform wander mode, are analysed based on their applicability for sustainability in terms of CO2 emissions. Life cycle analysis has been performed for the analysis period of 30 y for the pavement section of 10 km, along with fatigue predictions. Results show that zero wander mode generates more emissions as a result of premature fatigue damage under channelized loading. The uniform wander mode yields 20 % fewer emissions. Moreover, the use of full-depth reclamation during the pavement's Life Cycle improves the CO2 emissions by 15 % when compared to traditional removal and reconstruction methods. Therefore, the uniform wander mode is favourable for the improvement of pavement sustainability in terms of CO2 emissions.

Open Access: Yes

DOI: 10.3303/CET23107106

Road Safety and Sustainability: A Comparison of Country Rankings

Csaba Koren Ziyad N. Aldoski

Publication Name: Chemical Engineering Transactions

Publication Date: 2023-01-01

Volume: 107

Issue: Unknown

Page Range: 277-282

Description:

Road traffic deaths are a crucial problem in the world. At the same time, sustainability is a global issue. Numerous publications are dealing with road safety and sustainability separately as a basis for country rankings, but if you are searching for “road safety and sustainability”, no relevant results are found. The research question of this paper is: How is the safety performance of countries with good sustainability ranks? Vice versa: are countries with lower sustainability ranks more dangerous in traffic? To answer these questions, international sustainability and safety ranking scales were compared using Spearman correlation coefficients. The key finding of the paper is that there is a strong correlation between sustainability and the safety ranking of countries. However, there are some exceptions, countries with significantly different sustainability and safety performances.

Open Access: Yes

DOI: 10.3303/CET23107047

Impact of Traffic Sign Diversity on Autonomous Vehicles A Literature Review

Csaba Koren Ziyad N. Aldoski

Publication Name: Periodica Polytechnica Transportation Engineering

Publication Date: 2023-01-01

Volume: 51

Issue: 4

Page Range: 338-350

Description:

Traffic sign classification is indispensable for road traffic systems, including automated ones. There is a fundamental difference in the visual appearance of traffic signs from one country to another. Each dataset has its design standards and regulations based on shape, color, and information content, making implementing classification and recognition techniques more difficult. This paper aims to assess the influence of traffic sign diversity on autonomous vehicles (AVs) by reviewing several previous studies, comparing, summarizing their results, and focusing on classifying and detecting traffic sign datasets based on color, shape, and deep learning spaces using various methods and applications. Furthermore, it covers the main challenges facing road designers and planners considering changes to road safety infrastructure. It will be argued that compiling and standardizing a comprehensive global database of traffic signs is very difficult because it is costly and complex in application. However, it is still one of the possible solutions for the coming decades. Recommendations for future developments are also presented in this study.

Open Access: Yes

DOI: 10.3311/PPtr.21484

Impact of Autonomous Vehicles on Roundabout Capacity

Csaba Koren Attila Borsos Viktor Nagy Othmane Boualam

Publication Name: Sustainability Switzerland

Publication Date: 2022-02-01

Volume: 14

Issue: 4

Page Range: Unknown

Description:

Studying the impact of AVs on our road infrastructure offers a lot of potential in the transportation domain; one of these issues is how capacity will be affected. This paper presents a contribution to this research area by investigating the impact of AVs on the capacity of single-lane roundabouts using a microsimulation model. For the development of the model, a roundabout situated in Győr (Hungary) was selected and field data on the roundabout geometric characteristics as well as traffic volumes were used. Simulations using Vissim were run for various scenarios based on varying input traffic volumes and market penetration rates of AVs to assess queue lengths. The highway capacity manual (HCM) roundabout model was used to estimate the capacity of the existing roundabout. Values of follow-up times and critical gaps were set to decreasing as the penetration rate of AVs increases. The results demonstrated that 20% and 40% AVs in the flow would increase leg capacities by about 10% and 20%, respectively. Furthermore, a reduction in excessive queue lengths was estimated and capacities and queue lengths were calculated by legs. It was found that these are highly influenced by the distribution of flows among legs, and the share of flows in various directions.

Open Access: Yes

DOI: 10.3390/su14042203

Sight distances at unsignalized intersections: A comparison of guidelines and requirements for human drivers and autonomous vehicles

Mariusz Kieć Csaba Koren Attila Borsos Zsófia Magyari

Publication Name: Archives of Transport

Publication Date: 2021-01-01

Volume: 59

Issue: 3

Page Range: 7-19

Description:

Many traffic accidents are caused by unforeseen and unexpected events in a site that was hidden from the driver's eyes. Road design parameters determining required visibility are based on relationships formulated decades ago. It is worth reviewing them from time to time in the light of technological developments. In this paper, sight distances for stopping and crossing situations are studied in relation to the assumed visual abilities of autonomous vehicles. Current sight distance requirements at unsignalized intersections are based among others on speeds on the major road and on accepted gaps by human drivers entering or crossing from the minor road. Since these requirements vary from country to country, regulations and sight terms of a few selected countries are compared in this study. From the comparison it is remarkable that although the two concepts, i.e. gap acceptance on the minor road and stopping on the major road have different backgrounds, but their outcome in terms of required sight distances are similar. Both distances are depending on speed on the major road: gap sight distances show a linear, while stopping sight distances a parabolic function. In general, European SSD values are quite similar to each other. However, the US and Australian guidelines based on gap acceptance criteria recommend higher sight distances. Human capabilities and limitations are considered in sight field requirements. Autonomous vehicles survey their environment with sensors which are different from the human vision in terms of identifying objects, estimating distances or speeds of other vehicles. This paper compares current sight field requirements based on conventional vehicles and those required for autonomous vehicles. Visibility requirements were defined by three vision indicators: distance, angle of view and resolution abilities of autonomous cars and human drivers. These indicators were calculated separately for autonomous vehicles and human drivers for various speeds on the main road and for intersections with 90° and 60° angles. It was shown that the required sight distances are 10 to 40 meters shorter for autonomous vehicles than for conventional ones.

Open Access: Yes

DOI: 10.5604/01.3001.0014.9553

Can people recognize more than six road categories?

Gabriella Iván Csaba Koren Attila Borsos

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2019-01-01

Volume: 16

Issue: 6

Page Range: 207-222

Description:

The importance of human factors, in road design and traffic safety, has been increasing recently. As part of the human-centered design, schemata, as mental representations, induce road user expectations, as well as, trigger behavioral patterns. In road design this concept is called “self-explaining roads”, meaning that road users automatically drive according to an expected behavior and speed. This requires different categories of roads, each with homogenous characteristics and a notable difference between them. This paper investigates how many unique categories road users are able to recognize.

Open Access: Yes

DOI: 10.12700/APH.16.6.2019.6.13

Visibility studies at roundabouts entries

Csaba Koren Zsófia Magyari

Publication Name: Pollack Periodica

Publication Date: 2019-01-01

Volume: 14

Issue: 3

Page Range: 63-74

Description:

Most accidents in roundabouts occur at the entries, partly due to poor visibility. To analyse this problem a sample roundabout with some visibility obstacles was measured by laser scanner and data were put into a 3D model. The fields of view were studied from the viewpoint heights of car and truck drivers as well. To assess the results, three indicators were defined: the hidden sight distance, the hidden sight triangle area and the angle of hide. These indicators were measured in the point cloud model. Through these indicators the adequacy of visibility conditions can be assessed.

Open Access: Yes

DOI: 10.1556/606.2019.14.3.7

Searching possible accident black spot locations with accident analysis and gis software based on GPS coordinates

Csaba Koren Attila Borsos Pál Hegyi

Publication Name: Pollack Periodica

Publication Date: 2017-12-01

Volume: 12

Issue: 3

Page Range: 129-140

Description:

There are several methods for the analysis of road accidents in a road network. In Hungary from 2011 GPS coordinates are used to identify the location of personal injury accidents. This method significantly improves the display of locations of accidents on the map, which can be then analyzed using GIS tools. Accident black spots are the most dangerous places in road networks identified by the density of the accidents in the network. One of the analysis methods is the accident density searching. The methods and algorithms used in some software may show differences in relation to one another. The aim of this research is comparing two applications by investigating the local road network in Györ. The analysis was made using the WEB-BAL accident analysis software using the density-based spatial clustering of applications with noise procedure and the QGIS software using the kernel density estimation method. The former is the official accident database and online software used for accident investigations and the latter is an open source geographic information system. The results are visualized in accident density plots and black spot maps.

Open Access: Yes

DOI: 10.1556/606.2017.12.3.12

Forecasting travel time reliability in Urban road transport

Csaba Koren Tamás Mátrai Mattias Juhász

Publication Name: Archives of Transport

Publication Date: 2017-01-01

Volume: 43

Issue: 3

Page Range: 53-67

Description:

Assessment of travel time reliability as a fundamental factor in travel behaviour has become a very important aspect in both transport modelling and economic appraisal. Improved reliability could provide a significant economic benefit if it is adequately calculated in cost-benefit analyses for which the theoretical background has already been set. However, methods to forecast travel time reliability as well as travel behaviour models including its effects are rather scarce and there is a need for development in this field. Another important aspect could be the influencing factor of reliability in travel demand management and related policy-making. Therefore, this paper intends to further analyse reliability focusing exclusively on urban road transport based on automatic measurements of journey times and traffic volumes from a dataset of the city of Budapest. The main finding and the novelty of the study is a model which can forecast the standard deviation of travel times based on the volume-capacity ratio and the free-flow travel time. The paper also provides a real-life numerical experiment in which the proposed model has been compared with other, existing ones. It proves that besides existing mean-delay-based models, travel time reliability can be forecasted based on the volume-capacity ratio with an adequate accuracy.

Open Access: Yes

DOI: 10.5604/01.3001.0010.4227

Evaluation of the effects of auxiliary lanes on road traffic safety at downstream of U-turns

Csaba Koren Attila Borsos Andreas Vesper Inder Pal Meel

Publication Name: Transportation Research Procedia

Publication Date: 2017-01-01

Volume: 25

Issue: Unknown

Page Range: 1931-1945

Description:

To assess the safety impact of auxiliary lanes at downstream locations of U-turns, the Traffic Conflict Technique (TCT) was used. On the basis of the installed components at those locations, four types of U-turns were identified: those without any auxiliary lane, those with an acceleration lane, those with outer widening, and those with both an acceleration lane and outer widening. To give relative importance to high severity conflicts, weighting coefficients were used on the basis of the Czech TCT. The Severity Conflict Rate (SCR) was assessed by applying weighing coefficients to the observed conflicts related to the traffic volumes. According to the results, a comparatively highest value of SCR and a lowest level of road safety occurs if a location has no auxiliary lane. The highest level of road safety occurs if the layout includes a single component, either an acceleration lane or outer widening. If there are two components at the downstream zone, this causes larger area for conflict interactions and results in moderate level of road safety.

Open Access: Yes

DOI: 10.1016/j.trpro.2017.05.186

Recognition of built-up and non-built-up areas from road scenes

Gabriella Iván Csaba Koren Attila Borsos

Publication Name: European Transport Research Review

Publication Date: 2016-06-01

Volume: 8

Issue: 2

Page Range: Unknown

Description:

Purpose: In many cases, it does not follow from the road design, whether the given scene is within or outside the posted built-up area. The purpose of this paper is to evaluate road scenes, how far they can be considered being of built-up and non-built-up nature, as well as to identify road scenes which are ambiguous and therefore less safe. Methods: Two methods were used to assess the degree of unambiguous or ambiguous nature of road scenes. In the first approach, a survey of requested speeds at various road scenes was performed with 500 respondents. Here clearly non-built-up and built-up sites, as well as unclear sites were compared. In the second method, the recognition process of drivers was simulated by an image classification software. The classifier was trained by 100 clearly built-up and 100 non-built-up pictures. Four test runs followed, each using 200 pictures from different roads. Results: From the speed choice study, results have shown that in unclear situations (e.g. transition between built-up and non-built-up areas) the standard deviation of chosen speeds is higher than in unambiguous situations. In the image classification study the trained classifier worked well for road scenes which are definitely of built-up or non-built-up nature. Furthermore, as expected, for unclear situations, the classifier gave uncertain classifications. Conclusions: Each of the two methods produces an output indicator, the standard deviation of speeds and the certainty score, respectively. Both indicators can serve to identify road scenes leading to uncertain and therefore risky situations.

Open Access: Yes

DOI: 10.1007/s12544-016-0205-9

Getting an Insight into the Effects of Traffic Calming Measures on Road Safety

Csaba Koren Mattias Juhász

Publication Name: Transportation Research Procedia

Publication Date: 2016-01-01

Volume: 14

Issue: Unknown

Page Range: 3811-3820

Description:

The objective of this paper is to assess the significance of urban traffic calming and to get an insight into the safety impacts of local and area-wide traffic calming interventions enabling a better understanding and therefore 'better-informed' decisions on different schemes. Safety effects of traffic calming initiatives have been analysed on a city-level for larger Hungarian cities and an in-depth research has also been carried out for a more detailed case from the capital of Hungary. Results show that traffic calming initiatives have a very significant role in enhancing road safety of urban areas. Meanwhile the case study of Budapest explains observed effects in detail allowing for more accurate appraisal tools to be developed.

Open Access: Yes

DOI: 10.1016/j.trpro.2016.05.466

Safety Ranking of Railway Crossings in Hungary

Csaba Koren Attila Borsos Miklos Gabor

Publication Name: Transportation Research Procedia

Publication Date: 2016-01-01

Volume: 14

Issue: Unknown

Page Range: 2111-2120

Description:

Regarding traffic safety, railway crossings are crucial points in the rail and road network. In Hungary the safety ranking of railway crossings has been performed since 1993 and the results have been used for selecting unsafe locations and for prioritizing safety measures. Prioritization is based on a complex point system taking into account accident data, traffic volumes and various traffic engineering aspects. Weights of various indicators were based on engineering judgement. Although this method has been renewed a few times, there is a need to update this method involving more thorough statistical methods. The objective of this paper is to calibrate a new model and to compare it with previous models. A sample of about 1700 railway crossings satisfying a few requirements (railway with public service, traffic volume data available) was set up. The first part of the paper describes data collection. Five years (2010-2014) of accident data, AADT (Annual Average Daily Traffic) for rail and road, speed limits and further data (road pavement width, control devices, crossing angle, alignment, number of tracks, sight distances) were gathered. The modeling was conducted in two steps. First, each variable was entered into the model alone to see which ones significantly affect accident frequency. As a next step, two-variable models were built where expected injury accident frequency is predicted by annual daily road traffic and annual daily rail traffic. The sample was also split up into subgroups based on the type of control devices in order to analyze their effect on safety. Models are proposed using the Generalized Linear Modeling approach (GLM) assuming a negative binomial error structure. The results give estimation of the impacts of explanatory factors on the safety of railway crossings. Annual daily road traffic and annual daily train traffic are significant predictors. A number of predictors such as crossing angle, track alignment, number of tracks and sight distances turned out to be not significant. As far as the type of control devices are concerned, as expected coefficients are decreasing, hence safety is increasing in the following order: passive crossings, flashing lights, flashing lights + half barriers. Based on the above results, the complex point system used by practitioners for safety ranking was simplified considerably leaving out variables which turned out to be not significant.

Open Access: Yes

DOI: 10.1016/j.trpro.2016.05.226

Long-term safety trends as a function of vehicle ownership in 26 Countries

Csaba Koren Attila Borsos Nalini Ravishanker John Ivan

Publication Name: Transportation Research Record

Publication Date: 2012-01-12

Volume: Unknown

Issue: 2280

Page Range: 154-161

Description:

The objective of this paper was to model the evolution of road safety as a function of motorization level. The authors completed a country-level as well as a time-dependent analysis focusing on countries for which data were available for a long period of time (1965 to 2009). For the statistical analysis, a function describing road safety trends (decline, turning, improvement) was proposed. Two coefficients in the model were estimated for each country and for each year, and their change over time is discussed. The results showed that the shape of the curve changed over time. In some countries, the decrease in the mortality rate became slower over time; however, a greater potential to improve road safety existed in other countries. Possible reasons for the general positive trends in road safety are the continuous improvement in engineering solutions (better infrastructure, safer cars) as well as road users who are better trained and skilled because of education and experience. In addition to the factors mentioned previously, the increased speed by which safety-related information and knowledge are disseminated contributes to the decrease in the differences in safety levels among countries.

Open Access: Yes

DOI: 10.3141/2280-17

Recognition of road types and speed choice

Gabriella Iván Csaba Koren Attila Borsos

Publication Name: 6th IEEE Conference on Cognitive Infocommunications Coginfocom 2015 Proceedings

Publication Date: 2016-01-25

Volume: Unknown

Issue: Unknown

Page Range: 343-347

Description:

This paper outlines the recognition process of road types and its influence on speed choice. The appearance and spreading of the term "cognitive infocommunications" led the authors to rethink some of their earlier work from the cognitive perspective. In order to assess the recognition of road types and speed choice a picture sorting exercise and an on-line speed choice survey was completed. Limitations and extensions of the method are also considered.

Open Access: Yes

DOI: 10.1109/CogInfoCom.2015.7390616