Traffic Control Devices Research Articles

Analysis of Stopping Behavior at Rural T-Intersections Using Naturalistic Driving Study Data

Rural intersections account for around 30% of crashes in rural areas and 6% of all fatal crashes, representing a significant but poorly understood safety problem. Crashes at rural intersections are also problematic since high speeds on intersection approaches are present which can exacerbate the impact of a crash. Additionally, rural areas are often underserved with EMS services which can further contribute to negative crash outcomes. This paper describes an analysis of driver stopping behavior at rural T-intersections using the SHRP 2 Naturalistic Driving Study data. Type of stop was used as a safety surrogate measure using full/rolling stops compared to non-stops. Time series traces were obtained for 157 drivers at 87 unique intersections resulting in 1277 samples at the stop controlled approach for T-intersections. Roadway (i.e. number of lanes, presence of skew, speed limit, presence of stop bar or other traffic control devices), driver (age, gender, speeding), and environmental characteristics (time of day, presence of rain) were reduced and included as independent variables. Results of a logistic regression model indicated drivers were less likely to stop during the nighttime. However presence of intersection lighting increased the likelihood of full/rolling stops. Presence of intersection skew was shown to negatively impact stopping behavior. Additionally drivers who were traveling over the posted speed limit upstream of the intersection approach were less likely to stop at the approach stop sign.

STRUGGLE FOR SUSTAINABLE PUBLIC TRANSPORT IN SOUTHWESTERN NIGERIAN CITIES

Public transport contributes significantly to the development of socioeconomic activities and the long-term sustainability of all communities worldwide. Undoubtedly, it is a catalyst for maximizing quality urban living, social service accessibility, and environmental balance. Despite its considerable importance and benefits, public transport in Nigeria is still poorly practiced, and plagued by complex operational challenges. Based on this context, we assessed the public transport systems in Ikeja-Lagos, Abeokuta, and Ibadan cities to understand the struggle for sustainability in Nigeria. This study examined the socioeconomic and travel characteristics of passengers, the availability and condition of public transport infrastructural facilities, peculiar public transport challenges, and the best possible strategies to sustain public transport systems in Nigeria. The study employed a cross-sectional survey research design, while a multistage sampling technique was utilized to administer a well-validated questionnaire on the passengers at central transport nodes within the selected cities using both descriptive and inferential analysis. The results show that most of the respondents are men and spend more than 10% of their monthly income on public transport usage. Findings show that conventional public transport has been proven unpopular in Ibadan and Abeokuta cities compared to a chaotic and inadequate bus rapid system in Ikeja-Lagos. Findings also revealed traffic signal and control devices, and terminal facilities as top-two rated public transport facilities in good condition. The study revealed that public transport modes across the selected cities are operationally cracked as they are characterized by unprecedented challenges. The results of the Analysis of Variance established a statistical significant variation among the challenges mitigating sustainable public transport in the selected Nigerian cities. The study concludes and recommends, among other measures, full-adoption of appropriate mass transit options, particularly intra-city rail and the development of multimodal transport system.

Safe device solutions in railway traffic control systems

The paper deals with the problems of safe solutions of railway traffic control systems, using the example of modern solutions of protection systems applied at railway level crossings. The need for reliable, modern and safe railway traffic control devices has forced manufacturers in the railway industry to use high quality microprocessors in their structures. Devices used to safety traffic at intersections of railroads and roadways in one level shall be absolutely operational and reliable. Such solutions are the modern systems of automatic level crossing signaling made in computer technology. They use structural redundancy, programmable logic controllers, and have extensive self-diagnostic and technical diagnostic mechanisms. The paper presents selected analyses of railway traffic safety on the example of the automatic level crossing of system BUES 2000 type by Scheidt & Bachmann.

Understanding of Traffic Signs by Drivers on Urban Roads – A Case Study of Ilorin, Kwara State

The effectiveness of traffic signs, which are used often to promote safe driving and are designed to convey critical information quickly, is contingent on drivers' ability to understand them. Therefore, researchers in Ilorin set out to determine how well-understood and compliant traffic control devices were among drivers representing a range of demographics. The study was conducted using a descriptive survey research approach. The population for this study covers commercial and private drivers in Ilorin. The three local government areas in Ilorin were selected Ilorin South, East and West. A multi-stage sampling technique was used to select three hundred and eighty-four (384) drivers from the population for the study. The research instrument used for the study is a well-structured questionnaire. Statistics including frequency counts and percentages were used to examine the demographic information, the total proportion of drivers who properly recognized the traffic control device, and the variables that contribute to drivers' inability to comprehend traffic control devices. The average comprehension percentage of warning signs, regulatory signs, information sign, driver’s knowledge of road marking 56.1%, 60.3%, 64.6% and 59% respectively. The study's findings revealed that 60% of drivers in Ilorin generally comprehended traffic control devices.

Gaze Behaviors of Drivers Approaching Crosswalks with Different Sign and Crosswalk Treatments

Where do drivers look when approaching crosswalk locations with different sign and crosswalk treatments? This paper explores the gaze behavior of drivers approaching crosswalk locations at two study areas. The closed course study area evaluated the observation of traffic control devices (TCDs) placed in an otherwise sparse environment. The campus course area evaluated TCDs placed in visually complex environments. Driver gaze behavior was investigated to determine how TCDs were viewed in both day and night conditions as the drivers approached the crosswalks. Researchers found that drivers generally looked at crosswalk markings for a longer time at night than during the day at both the closed course and campus course locations. Nighttime observations of traffic signs were significantly longer than daytime observations on the closed course area, but not significantly longer at the campus course. In general, the crosswalks were found to capture more gaze time than the signs. Signs captured less attention and, in some cases, no direct eye-gazes during the evaluation time frame. When considering the gaze patterns when no TCDs were present, there were typically increases in gazes at the signs. It was observed that gaze values were generally higher for the closed course where there was no traffic and minimal distractions. Distractions and complex driving environments may shift drivers’ attention from the roadway and TCDs, thus requiring the design, implementation, and maintenance of TCDs such that they are easily interpreted and not visually dissolved in the abundance of visual disturbances of a complex environment.

Findings from a Survey on Bus Stop Design

The bus stop is the first point of contact between the passenger and the bus service. The spacing, location, and design of bus stops significantly influence transit system performance and customer satisfaction. At present, relatively few transit agencies have comprehensive reference material available to assist in bus stop location and design. In recognition of the importance of bus stop location and design, the Transit Cooperative Research Program (TCRP) sponsored research to develop guidelines for locating and designing bus stops in various operating environments. These guidelines can assist transit agencies, local governments, and others (e.g., developers) in locating and designing bus stops that consider bus patrons’ convenience, safety, and access to sites, as well as safe and efficient transit operations and traffic flow.Mail-out surveys were conducted as part of the TCRP bus stop location and design guidelines project. The mail-out surveys, which were an initial task of the project, were used to determine current practices and areas of concern regarding bus stop design for transit agencies and states. Less than half of the responding transit agencies currently use guidelines or manuals, which indicates a need for the document being developed. Furthermore, almost every agency has moved a bus stop to improve traffic operations and more than half have redesigned a curbside stop to a bus bay or nub design.Transit agencies are typically responsible for establishing routes, stop spacing, stop location (near side, far side, or midblock), type of stop (curbside, bus bay, or nub), bus stop signs, and amenities (such as street furniture). Functions jointly shared by transit agencies and cities, counties, and states include selecting the length of the bus stop zone, selecting pavement design at bus stops, removal of parking for bus stops, bus stop relocation due to traffic, and bus priority measures. Selecting and maintaining traffic control devices is primarily a city function. The categories considered during the bus stop location and design process are (in descending order): bus operations, area type or land use, passenger safety, roadway features, and traffic conditions.

Road Markings and Signs in Road Safety

Due to the dynamic nature and complexity of road traffic, road safety is one of the most demanding social challenges. Therefore, contemporary road safety strategies incorporate a multidisciplinary and comprehensive approaches to address this problem and improve the safety of each individual element, i.e., the human, vehicle, and road. Traffic control devices are an important part of road infrastructure, among which road markings and road signs play a significant role. In general, road markings and signs represent basic means of communication between the road authorities and road users and, as such, provide road users with necessary information about the rules, warnings, obligations, and other information related to the upcoming situations and road alignment. The aim of this entry is to briefly present the main functions and characteristics of road markings and signs, and their role in road safety. In addition, practical issues and future trends and directions regarding road markings and signs are discussed.

Crash/Near-Crash Analysis of Naturalistic Driving Data Using Association Rule Mining

This study explores the associations between crash/near-crash (C/NC) events and roadway, driver-related, and environmental factors in naturalistic driving studies (NDS). We used the Naturalistic Engagement in Secondary Tasks (NEST) dataset, which is massive and detailed and contains 50 million miles of naturalistic driving data resulting from the Strategic Highway Research Program 2 (SHRP2). Association rule mining (ARM) is applied to extract the rules for frequently occurring events. The generated association rules are filtered by four metrics (support, confidence, lift, and conviction) and validated by the lift increase criterion. A three-step analysis is performed to obtain a comprehensive understanding of the rules of C/NC events. The 20 most frequent items are first selected to investigate their relationship with the C/NC events. Subsequently, the association rules are used to identify the factors contributing to C/NC events. Finally, correlations between contributing factors and different severities of crashes (I—most severe, II—police-reportable, III—minor crash, and IV—low-risk tire strike) are analyzed by ARM. The results demonstrate that C/NC events occur most frequently on straight and level road segments with no controlled intersections or traffic control devices when drivers are performing secondary tasks. Thus, the reasons for these crashes are carelessness and overconfidence. In addition, a median strip or barrier and a wider road can significantly reduce the frequency and severity of crash events. Moreover, gender, age, average annual mileage, and secondary tasks are highly correlated with the frequency and severity of C/NC events. Drivers with visual-spatial disabilities or crash records are more likely to be involved in the most severe crash events. Near-crash events occur more frequently at higher traffic density and on roads with traffic control devices and controlled intersections. These conditions may keep drivers alert, preventing crashes.

Assessment of Drivers and Passengers Seat Belt Compliances in Baghdad City

Baghdad city population is growing rapidly and soon it will reach 10 million, and this has increased the number of drivers on city streets which accompanied with the absence of adequate traffic enforcement and traffic control devices to match this increase. Current research main objective is to assess city drivers and passenger’s compliance to use seat belts as a safety precaution. The study consists of two main surveys conducted in the field considering gender, vehicle type, and other drivers characteristics. The first one consists of a questionnaire asking respondents to answer multiple choice questions about seat belt use and other questions associated with respondents’ demographics. Whereas second part involves observing seat belt use among city drivers and passengers at selected locations. Also, we sought information about seat belt use as a driver, front seat passenger, and rear seat passenger. Only 20% of the sample in field observational survey were wearing seat belt as a driver. Printed questionnaire reveals that only 12% are used to buckle up all the time, and 28% never use seat belt in their life, and the rest use seat belt occasionally. Seat belt rates for passengers were 5% only, and most passengers do not care about seat belts and many cars have disabled or malfunction seat belts. Four reasons for putting seat belt were considered and ranked as to avoid injuries, to avoid fines, to follow seat belt law, and wearing seat belt when people in the same car are wearing it.

Comprehension Analysis of Traffic Signs by Drivers on Urban Roads in Ilorin, Kwara State

Traffic signs are the oldest and most commonly used Traffic Control Device (TCD). These signs convey messages in words or symbols and erected to regulate, warn, or guide the road users (motorists, and pedestrians). This study investigated the level of compliance of traffic control devices among drivers with different sociodemographic characteristics in Ilorin. A descriptive research design of survey type was used in the conduct of the study. The population for this study covers commercial and private drivers in Ilorin. The research instrument used for the study is a well-structured questionnaire. The data gathered were analysed using frequency counts and percentage for the demographic data, and factors that affect the non-understanding of drivers to traffic control devices. Statistical analysis was done with SPSS. For chi- square, only the years of driving experience was found statistically significant with a p-value of 0.006 and for Analysis of Variance (ANOVA) both educational experience and years of driving experience were found to be statistically significant with p-value of 0.001 and 0.000. It was deduced that major factors affecting the non-understanding of traffic control devices by drivers in Ilorin were lack of previous knowledge of the signs, lack of adequate enforcement and non-availability of control devices on most roads in Ilorin.

Intersection two-vehicle crash scenario specification for automated vehicle safety evaluation using sequence analysis and Bayesian networks

This paper introduces a test scenario specification procedure using crash sequence analysis and Bayesian network modeling. Intersection two-vehicle crash data was obtained from the 2016–2018 National Highway Traffic Safety Administration (NHTSA) Crash Report Sampling System (CRSS) database. Vehicles involved in the crashes are specifically renumbered based on their initial positions and trajectories. Crash sequences are encoded to include detailed pre-crash events and concise collision events. Based on sequence patterns, the crashes are characterized as 55 types. A Bayesian network model is developed to depict the interrelationships among crash sequence types, crash outcomes, human factors, and environmental conditions. Scenarios are specified by querying the Bayesian network’s conditional probability table. Distributions of operational design domain (ODD) attributes (e.g., driver behavior, weather, lighting condition, intersection geometry, traffic control device) are specified based on conditions of sequence types. Also, distribution of sequence types is specified on specific crash outcomes or combinations of ODD attributes.

Propaedeutic of the methodology of improving electromagnetic compatibility of railway traffic control systems in relation to the implementation of the EMC4CCS - BRIK project

The purpose of this article is to introduce to the methodology of increasing electromagnetic compatibility in distributed system, on the example of the implementation of works in the field: "Research and improvement of electromagnetic compatibility of railway traffic control devices and rolling stock", which are the subject of the BRIK project. The methodology is defined here as a set of rules for conducting research in order to achieve an intended goal. The article proposes a procedure to improve the EMC condition of distributed systems. For monitoring the quality of the system operation in terms of electromagnetic compatibility, the implementation of the OEE indicator was suggested.

Incident Duration Time Prediction Using Supervised Topic Modeling Method

Accurate prediction of the duration of traffic incidents is one of the most prominent prerequisites for effective implementation of proactive traffic incident management strategies. This paper presents a novel method for immediate prediction of traffic incident duration using an emerging supervised topic modeling. The proposed method employs natural language processing techniques for semantic text analysis of the text-based incident traffic incident dataset. The model applies the labeled latent Dirichlet allocation approach, and it is trained using 1,466 incident records collected by the Korea Expressway Corporation from 2016 to 2019. For training purposes, the proposed method divides the incidents into two groups based on the incident duration: incidents shorter than 2 h and incidents lasting 2 h or longer, following the incident management guidelines of the Federal Highway Administration Manual on Uniform Traffic Control Devices for Streets and Highways (2009). The model is tested with randomly selected incident records that were not used for the model training. The results demonstrate overall prediction accuracies of approximately 74% for incidents lasting up to 2 h, and 82% for incidents lasting 2 h or longer.

Estimating effectiveness of speed reduction measures for pedestrian crossing treatments using an empirically supported speed choice modeling framework

Pedestrian crossing treatments, such as Pedestrian Hybrid Beacons (PHBs) and Rectangular Rapid-Flashing Beacons (RRFBs), are traffic control devices implemented to help pedestrians safely cross busy or higher-speed roadways at midblock crossings and uncontrolled intersections. This study aims to assess the effectiveness of the PHB and RRFB by analyzing drivers’ speeding behavior under different roadway types with real-life traffic conditions. In order to understand the effect of pedestrian crossing treatments (i.e., PHB and RRFB) have on drivers’ speeding behavior, this paper analyzes four zones (i.e., one upstream zone and three consecutive downstream zones). For the four analysis zones, different indexes were computed which corresponds to the differences in drivers’ speed when encountered with the pedestrian crossing treatments. A grouped random effect hurdle beta regression model is estimated for the indexes, with a fixed effect hurdle beta model used for comparison and validating the importance of considering the grouped random heterogeneity across participants. The proposed analysis framework was validated by the means of an empirical driving simulator study, based on two urban roads in the Central Florida region, North Alafaya Trail (SR-434) and South Orange Blossom Trail (US-441). The results revealed that the proposed modeling framework reflects drivers’ difference in speed for the different pedestrian crossing treatments. The results suggest that with proper understanding of the PHB, the PHB can reduce drivers speed even beyond the location of the PHB. Meanwhile, the RRFB does have some effect in speed reduction beyond the location of the RRFB, however many drivers failed to acknowledge the RRFB. It is suggested that when drivers’ have proper education on the use of the PHB to reduce speed safely and for the installation of RRFB be on roads with two or less lanes and a speed limit less than 40 mph. While the main purpose of the pedestrian crossing treatments is to help pedestrians cross safely, speed reduction can be considered a byproduct as revealed in this study.

Traffic safety analysis at interchange exits using the surrogate measure of aggressive driving behavior and speed variation

Because of heavy traffic on urban expressways, the exits of expressway interchanges have become accident-prone sites. This study explores the impacts of various traffic control devices and road conditions on road safety at interchange exits based on driving behavior data from navigation software. The traffic order index (TOI) based on driving behavior and speed variation is used to evaluate road safety. The general safety characteristics and partitioned safety characteristics of interchange exit sections for different traffic control devices and under different road conditions were described, and a structural equation model (SEM) was constructed to observe the influences of the traffic control devices, road conditions, congestion degree, and time on road safety. The results show that traffic control devices (the number of warning signs, number of advance exit signs and complexity of diagrammatic guide signs) and road conditions (the number of lanes and merging conflicts within 500 m) have significant influences on the road safety of interchange exits. Road conditions have the greatest impact on the safety of interchange exits, followed by the congestion index, traffic control devices, and time. The results could help traffic management departments reconstruct or rehabilitate traffic control devices and enable reasonable road planning at interchange exits. The safety evaluation method for traffic control devices and road conditions based on driving behavior data collected from navigation software could be further used on other roads.

Pavement Marking Practices, Standards, Applications, and Retroreflectivity

Pavement markings are important elements of roadway networks and help guide traffic flow in an orderly manner. In recent years, transportation agencies are facing challenges to manage pavement markings because of the advent of new vehicle technologies. Existing pavement marking standards were developed for serving human road users but they may not be effective for both human drivers and machine vision systems. Therefore, the National Committee on Uniform Traffic Control Devices suggested amendments to the current pavement marking standards. Therefore, it is necessary to explore pavement marking practices for a variety of states. With this aim, the Wyoming Technology Transfer Center conducted an online survey as part of a comprehensive research project on developing pavement marking management plans for the Wyoming Department of Transportation. The main objective of the survey is to document the various state Departments of Transportation (DOTs’) pavement marking management plans, how the plans are developed, strategies for pavement marking data collection, and pavement marking retroreflectivity. The survey has 31 questions dealing with pavement marking striping, pavement marking data collection, pavement marking retroreflectivity, and a few miscellaneous questions. There are 29 DOTs who responded to the survey. This paper summarizes the responses from the survey on evaluating pavement marking management practices at a national level.

Improved Practices for Temporary Work Zone Guide Signs

Freeway reconstruction projects often involve adding lanes and improving entrance and exit ramps. Sign supports for overhead guide signs are sometimes removed early in the project to make way for construction activities. In addition, roadside guide signs may need to be relocated and replaced with temporary guide signs. The Manual on Uniform Traffic Control Devices provides guidance for work zone guide signs in Part 6, stating that temporary guide signs shall have black legend and border on an orange background. But permanent guide signs follow Part 2 of the MUTCD, which prescribes white legend and border on a green background for guide signs in general. Thus, many long-term freeway work zones may have guide signs in both color schemes that change throughout the project as the construction work progresses. The constrained conditions often seen in these work zones can also result in guide signs that use a variety of fonts, font sizes, sign sizes, and placement positions. This paper describes the human factors study that was performed to assess motorist understanding of various work zone guide signage strategies. Based on the results, the researchers were able to develop recommendations for long-term work zone guide sign design and placement to improve uniformity for the traveling public.

Causal mediation analysis of the impacts of distracted driving on crash injury risks

Distracted driving can pose great risks to road traffic safety. Although there is a rich body of literature devoted to identifying the statistical association between distracted driving and crash risks, few are available to examine the causal effect mechanism of distracted driving. Thus, the study attempts to conduct the causal mediation analysis to reveal the impact mechanism of distracted driving on crash injury risks, in which various hazardous driving actions are used as the mediators between driver distraction and crash injuries. Sensitivity analysis is also carried out to validate the underlying assumption of causal mediation analysis. The analytic results indicate that 1) distracted driving can lead to a higher likelihood of hazardous driving actions such as failing to yield, disobeying traffic control devices, driving left of lane center, and failing to stop in assured clear distance, 2) both the driver distraction and hazardous actions are the contributory factors to the severe crash injuries, and 3) distracted driving is identified to have significant mediation effects on crash injury risks. The study confirms the causal mediation effects of distracted driving on crash injury risks, which can serve to propose specific safety countermeasures to mitigate the crash injury risks.

COVID-19 and Injury Severity of Drivers Involved in Run-Off-Road Crashes: Analyzing the Impact of Contributing Factors

This study examined the relationship between the lockdown during the COVID-19 pandemic and the severity of injuries sustained by drivers involved in run-off-road (ROR) crashes. A random parameter ordered logit (RPOL) modeling framework was utilized to account for the ordinal nature of severity outcome and capture the potential unobserved heterogeneity. The data used in this study contained ROR crashes that occurred in the state of Florida from April to September for 2019 and 2020 representing non-pandemic and pandemic time periods, respectively. Separate driver injury severity models were developed across the two time periods, and the overall stability of the model estimates was examined through likelihood ratio tests. The impacts of various potential contributing factors, including crash-, driver-, and vehicle-related variables, roadway geometric characteristics, environmental conditions, and traffic-specific factors, were assessed. Although the developed models share some common features, the analysis results showed that the model specifications indicated a strong temporal instability among the estimated parameters. Compared to the non-pandemic period, the following variables resulted in increased driver injury severity in ROR crashes during the pandemic: drivers 65 years or older, careless driving, and absence of traffic control devices.

Road-Type Detection Based on Traffic Sign and Lane Data

Establishing the current road type constitutes a significant assistance to car drivers, as, by default, the road type determines the legal speed limit. Although there are GPS- and map-based navigation systems that can retrieve the actual road type and speed limit and some can even access and indicate current traffic volumes, it was our aim to develop and test a software prototype of a road-type detection (RTD) system that relies solely on video and sensor data collected on board. Such a system can still work during GPS signal outages. The study presents a heuristic approach to RTD that is based on type and distance data relating to traffic control devices (TCDs) installed along a road. The road is used by an ego vehicle with an on-board smart camera looking ahead and with a number of vehicular sensors. A complex processing step—not detailed in the study—detects TCDs with reasonable probability and error rate and locates them with respect to a 3D coordinate frame fixed to the ego vehicle. The prototype system takes data describing the detected TCDs as its input. This data are then evaluated in a multiscale manner by computing empirical statistics of occurrences over short, medium, and long patches of road. Such an evaluation is carried out in conjunction with each considered road type, and the resulting values are compared to respective reference values. Heuristics is then used in decision-making to resolve any interscale and interroad-type disaccords. The proposed decision rules take into account the possibility of TCDs having been missed and of faulty detections. Short preprocessed synchronised video and signal sequences recorded in different countries and road environments were used for testing the prototype system. These short sequences were carefully strung together into coherent chains. Distance-based recognition precisions 78.9% and 88.9% were gained for European (continental) and for UK roads, respectively.