Highway Railroad Grade Crossings Research Articles

Machine Learning Approach to Enhance Highway Railroad Grade Crossing Safety by Analyzing Crash Data and Identifying Hotspot Crash Locations

Safe railway operation is vital for public safety, the environment, and property. Concurrent with climbing amounts of rail traffic on the Canadian rail network are increases in the last decade in the annual crash counts for derailment, collision, and highway railroad grade crossings (HRGCs). HRGCs are important spatial areas of the rail network, and the development of community areas near railway tracks increases the risk of HRGC crashes between highway vehicles and moving trains, resulting in consequences varying from property damage to injuries and fatalities. This research aims to identify major factors that cause HRGC crashes and affect the severity of associated casualties. Using these causal factors and ensemble algorithms, machine learning models were developed to analyze HRGC crashes and the severity of associated casualties between 2001 and 2022 in Canada. Furthermore, spatial autocorrelation and optimized hotspot analysis tools from ArcGIS software were used to identify hotspot locations of HRGC crashes. The optimized hotspot analysis shows the clustering of HRGC crashes around major Canadian cities. The analysis of cluster characteristics supports the results obtained for causal factors of HRGC crashes. These research outcomes help one to better understand the major causal factors and hotspot locations of HRGC crashes and assist authorities in implementing countermeasures to improve the safety of HRGCs across the rail network.

Identifying Risk Factors for Autos and Trucks on Highway-Railroad Grade Crossings Based on Mixed Logit Model.

This study aimed to determine different influencing factors associated with the injury outcomes of heavy vehicle and automobile drivers at highway-rail grade crossings (HRGCs). A mixed logit model was adopted using the Federal Railroad Administration (FRA) dataset (n = 194,385 for 2011-2020). The results show that drivers' injury severities at HRGCs are enormously different between automobile and truck/truck-trailer drivers. It was found that vehicle speed and train speed significantly affect the injury severity in automobile and truck drivers. Driver characteristics such as gender and driver actions significantly impact the injury severity in automobile drivers, while HRGC attributes such as open space, rural areas, and type of warning device become significant factors in truck models. This study gives us a better understanding of the differences in the types of determinants between automobiles and trucks and their implications on differentiated policies for car and truck drivers.

Dense Traffic Detection at Highway-Railroad Grade Crossings

In the United States, highway-railroad grade crossings are easily congested, which not only causes significant traffic delays to travelers but also brings potential threats to the first responders for emergencies. Unfortunately, very limited research efforts have been dedicated to developing practical systems that can assess traffic conditions at overcrowded grade crossings. The main challenge in evaluating the congestion conditions at the crossings is the different instance classes (i.e., vehicle, train, and pedestrian) that need to be accurately detected, especially when densely packaged. In this study, a novel convolutional neural network (CNN) named dense traffic detection net (DTDNet) is developed. DTDNet proposes to integrate the Transformer Attention (TA) module for better modeling of global context information and the learning-to-match detection head for optimizing object detection and localization using a likelihood probability fashion. To train and test DTDNet, a unique grade crossing traffic image dataset including congested and normal traffic during both daytime and nighttime is established. Experimental results on the dataset show that the proposed DTDNet achieves the maximum mean average precision (mAP) value, 0.832, outperforming the other state-of-the-art (SOTA) models. Field test results with low mean average error (MAE), mean relative error (MRE), and root mean squared error (RMSE) which are 2.200, 1.890, and 0.280, respectively suggest the proposed model has a satisfying and robust performance in the field application under different environments.”.

Computer vision-based approach for smart traffic condition assessment at the railroad grade crossing

Slow-moving or stopped trains at highway-railroad grade crossings, especially in the populated metropolitan areas, not only cause significant traffic delays to commuters, but also prevent first responders from timely responding to emergencies. In this study, the researchers introduce an automated video analysis, detection and tracking system to evaluate the traffic conditions, analyze blocked vehicle behaviors at grade crossings, and predict the decongestion time under a simplified scenario. A novel YOLOv3-SPP+ model has been developed to improve the detection performance with dividing the image from finer to coarser levels and enhance local features. The SORT module has been integrated to the model for a simple yet efficient manner to track vehicles at the railroad grade crossing. Two field datasets at the Columbia, SC, with train blockage video records have been tested. The model training performance has been evaluated by mAP @0.5, F1 score, and total loss. Based on the training results, our model outperforms other YOLO series models. The field tracking performance has been assessed by the ratio between prediction and ground truth. The mean value of accuracy of our test cases is 92.37%, indicating a reliable tracking performance. In addition, the present results indicate the traffic during and after the crossing blockage does follow a pattern, and there is a general trend of the behavior of the vehicles waiting or taking an alternative route. A good linear correlation between the decongestion time and the number of blocked vehicles has been observed at the monitored grade crossing at the City of Columbia, SC.

An integrated clustering and Bayesian approach to investigate the severity of pedestrian collisions at highway-railway grade crossings collisions

This study aims at developing a solid understanding of the contributing factors to pedestrian fatal and injury collisions at highway-railway grade crossings (HRGC), along with the impact of different warning devices that are commonly used at HRGCs. The study utilized integrated Machine Learning and Bayesian models to analyze the United States HRGC collision using the Federal Railroad Administration database between 2009 and 2018. The results demonstrate the association between different factors and the collision severity in each cluster and attempt to explain the inconsistency associated with the impact of some factors, such as weather conditions and pedestrian traits, on collision severity. The results also highlighted the conditions at which the different types of countermeasures and warning devices are most effective and the circumstances that limit their benefits. The results confirmed the benefits of the proposed analysis approach, in which collision data are classified into a group of clusters first before investigating the impact of the different factors on collision severity. The results wills support engineers and planners to develop specific policies and designs that aim at mitigating severe collisions at HRGCs and enhance pedestrian safety.

Pedestrian and bicyclist behavior at Highway-Rail grade crossings: An observational study of factors associated with violations, distraction, and crossing speeds during train crossing events

Pedestrian-train collisions at highway-railroad grade crossings (HRGCs), though relatively rare events, often result in severe injuries or fatalities. In the ten year period from 2008-2017, there were 1,470 pedestrian-train collisions reported in the United States resulting in 908 fatalities and 492 injuries according to the Federal Railroad Administration. Furthermore, pedestrians in over 27% of these crashes were coded as disregarding gates at HRGCs, indicating unsafe behavior at these crossings may lead to crashes. In order to examine this behavior (for both pedestrians and bicyclists) and add to the body of knowledge for this topic, this observational study utilized pedestrian and bicyclist behavior data extracted from videos of HRGCs. Several pedestrian and bicyclist behavior characteristics were extracted including the prevalence of pedestrian and bicyclist violation (e.g., disregarding active devices), pedestrian and bicyclist distraction, and pedestrian and bicyclist crossing speeds. Using these data, along with rail-grade crossing features, train crossing parameters, and demographic data, statistical analyses were performed to examine factors significantly associated with pedestrian and bicyclist violations, distraction, and crossing speeds at HRGCs. Ultimately, the results of this study provide important information which may be useful in planning strategies to mitigate the impacts of unsafe pedestrian or bicyclist behavior at HRGCs.

Market basket analysis of safety at active highway-railroad grade crossings

IntroductionData from the Federal Railroad Administration show high numbers of incidents at the approximately 210,446 highway-railroad grade crossings across the United States. One cause for this unsettling trend is the problem of drivers stopping within the dynamic envelope zone (DEZ) of the train while in queue. This research seeks to study DEZ stopping behavior at highway-railroad grade crossings by evaluating regulatory signage and further analyze variables that may affect this behavior. Method: A comparative safety analysis is undertaken to evaluate the effectiveness of the standard “Do Not Stop on Tracks” (R8-8) sign by using percentage change calculations and chi-squared tests. The study then conducts a market basket analysis (MBA) to extrapolate on these results and to identify underlying factors associated with observed driver behavior using variables influenced by visibility, perception, and maneuverability. Results: Rather low reductions in safety violations resulted from the R8-8 installation, including a 2.2% reduction in DEZ stopping behavior and only a slight 3.7% increase in compliance. The results of the MBA identified associations that affirmed assumptions about driver behavior, while other associations were not as direct but altogether helped broaden the understanding of interactions at grade crossings. Conclusions: This study concluded that the R8-8 had a positive but minimal effect on driver behavior at the grade crossings. The MBA successfully demonstrated its value by providing further insight on the safety analysis and by increasing the number of variables that can be analyzed simultaneously. The methodology offers the scientific community an innovative approach to analyzing driver behavior. Practical Applications: The results identified important variables for developing preventive measures, which will ultimately help reduce safety violations at grade crossings. The MBA can provide practical insight for railroad safety professionals and transportation engineers when determining problematic intersections and can be used to improve the education on grade crossing interactions.

Evaluating the Impact of Highway-Railway Grade Crossings on Travel Time Reliability on a Highway Network Level

Highway-rail grade crossings (HRGCs) have a range of safety and operational impacts on highway traffic networks. This paper illustrates a methodology for evaluating travel-time reliability for the routes and networks affected by trains traveling through HRGCs. A sub-area network including three HRGCs is used as the study network, and a simulation model calibrated to local traffic conditions and signal preemption strategies using field data is used as the platform to generate travel time data for analysis. Time-dependent reliability intervals for route travel time are generated based on route travel-time means and standard deviations. OD level reliability is calculated using a generic reliability engineering approach for parallel and series systems. The route travel time reliability results can be provided as real-time traffic information to assist drivers’ route-choice decisions. The OD level reliability is a way to quantify the impact of HRGCs on highway network operation. This effort fills the gap of reliability research for HRGCs on the route and sub-area network level, and contributes to improving the efficiency of decision-making for both traffic engineers and drivers.

Benchmarking regions using a heteroskedastic grouped random parameters model with heterogeneity in mean and variance: Applications to grade crossing safety analysis

Comparing regions while adjusting for differences in characteristics of sites located in those regions is valuable since it identifies possible inter-regional dissimilarities in crash risk propensities according to specific safety performance measures (e.g., crash frequency of a specific type). This paper describes a framework to benchmark different regions (neighborhoods, provinces, etc.) in terms of a selected safety performance measure. To avoid issues relating to aggregated (macro-level) data, we use disaggregate (micro-level) data to draw inferences at a macro/region-level, which is often needed for developing large-scale transportation safety and planning programs and policies. To overcome unobserved heterogeneity, we employ a multilevel Bayesian heteroskedastic Poisson lognormal model with grouped random parameters allowing heterogeneity in both mean and variance parameters. The proposed approach is illustrated through a comprehensive study of highway railway grade crossings across Canada. The results indicate that the proposed model addresses unobserved heterogeneity more efficiently and provides more insight compared to conventional random parameters models. For example, we found that as traffic exposure increases, grade crossing safety deteriorates at a higher rate in the Canadian Prairies than in the other regions. Our benchmarking framework is also affected by different model specifications. The results indicate the need for further in-depth investigations, which could help to identify possible reasons for inter-region differences in terms of specific safety indicators. This study provides valuable guidelines to Canadian transportation authorities, revealing important underlying crash mechanisms at highway railway grade crossings in Canada.

Improved Pedestrian Sight-Distance Needs at Railroad-Highway Grade Crossings

AbstractThis paper presents an improved model for pedestrian crossing time that is used to establish preliminary guidelines for lateral clearance needs on railroad-highway grade crossings. The impr...

Analyzing injury severity factors at highway railway grade crossing accidents involving vulnerable road users: A comparative study

ABSTRACTObjective: The main objective of this study is to identify the main factors associated with injury severity of vulnerable road users (VRUs) involved in accidents at highway railroad grade crossings (HRGCs) using data mining techniques.Methods: This article applies an ordered probit model, association rules, and classification and regression tree (CART) algorithms to the U.S. Federal Railroad Administration's (FRA) HRGC accident database for the period 2007–2013 to identify VRU injury severity factors at HRGCs.Results: The results show that train speed is a key factor influencing injury severity. Further analysis illustrated that the presence of illumination does not reduce the severity of accidents for high-speed trains. In addition, there is a greater propensity toward fatal accidents for elderly road users compared to younger individuals. Interestingly, at night, injury accidents involving female road users are more severe compared to those involving males.Conclusions: The ordered probit model was the primary technique, and CART and association rules act as the supporter and identifier of interactions between variables. All 3 algorithms' results consistently show that the most influential accident factors are train speed, VRU age, and gender. The findings of this research could be applied for identifying high-risk hotspots and developing cost-effective countermeasures targeting VRUs at HRGCs.

Investigating risk factors of traffic casualties at private highway-railroad grade crossings in the United States

Private highway-railroad grade crossings (HRGCs) are intersections of highways and railroads on roadways that are not maintained by a public authority. Since no public authority maintains private HRGCs, fatal and injury crashes at these locations are of concern. However, no study has been conducted at private HRGCs to identify the safety issues that might exist and how to alleviate them. This study identifies the significant predictors of traffic casualties (including both injuries and fatalities) at private HRGCs in the U.S. using six years of nationwide crashes from 2009 to 2014. Two levels of injury severity were considered, injury (including fatalities and injuries) and no injury. The study investigates multiple predictors, e.g., temporal crash characteristics, geometry, railroad, traffic, vehicle, and environment. The study applies both the mixed logit and binary logit models. The mixed logit model was found to outperform the binary logit model. The mixed logit model revealed that drivers who did not stop, railroad equipment that struck highway users, higher train speeds, non-presence of advance warning signs, concrete road surface type, and cloudy weather were associated with an increase in injuries and fatalities. For example, a one-mile-per-hour higher train speed increases the probability of fatality by 22%. On the contrary, male drivers, PM peak periods, and presence of warning devices at both approaches were associated with a fatality reduction. Potential strategies are recommended to alleviate injuries and fatalities at private HRGCs.

First responders' response area and response time analysis with/without grade crossing monitoring system

In North America, highway–railway grade crossings can lead to significant travel delays for emergency responders trying to reach an incident. Grade separation cannot be justified for most grade crossings, but a grade crossing monitoring system (GCMS) can detect a blockage and communicate the information to local emergency dispatchers in real-time. As every minute can be critical in emergency work, the potential for such systems clearly needs investigation. Saskatoon, Saskatchewan has numerous grade crossings and blockages caused by long slow moving or stationary freight trains. This study uses two Geographic Information System based analyses: service area analysis to show how the fire responders' service area changes with and without a grade crossing blockage; and network analysis to estimate the impact of GCMS on fire responders' response times both with and without a blockage. Both analyses are quantitative and both can present the results visually. The results from our examples in Saskatoon show significant savings in response times by, for example, avoiding detours made on the assumption that a road is blocked, avoiding taking a route found to be blocked and then having to take a detour, and choosing to wait at a crossing for a blockage to clear when the GCMS indicates that this is more efficient than taking a detour route. Although all cities and road networks are different, this study demonstrates that a GCMS can benefit certain jurisdictions by improving their emergency services and saving lives and property.

Contributing factors of crash injury severity at public highway-railroad grade crossings in the U.S.

The Moving Ahead for Progress in the 21st Century (MAP-21) includes a separate program that supports safety improvements to reduce the number of fatalities and injuries at public highway-railroad grade crossings (HRGCs). This study identifies the significant factors affecting crash injury severity at public HRGCs in the United States. Crashes from 2009 through 2013 on 5,528 public HRGCs, extracted from the Federal Railroad Administration database, were used in the analysis. A comprehensive list of risk factors was explored. Examples include predictors related to geographic region of crash, geometry (e.g., area type and pavement marking type), railroad (e.g., warning device type and railroad class), traffic (e.g., train speed and vehicles annual average daily traffic "AADT"), highway user (e.g., driver age and gender), and environment (e.g., lighting and weather conditions). The study used the mixed logit model to better capture the complex highway user behavior at HRGCs. Female highway users were at higher risk of involvement in injuries and fatalities compared to males. Higher train speeds, very old drivers, open areas, concrete road surface types, and railroad equipment striking highway users before crash, were all found to increase the injury likelihood. On the other hand, young and middle-age drivers, non-passing of standing vehicles at HRGCs, industrial areas, and presence of warning bells were found to reduce injuries and fatalities. The mixed logit model succeeded in identifying contributing factors of crash severity at public HRGCs and potential countermeasures to reduce both fatalities and injuries are suggested. It is important to install warning bells at public HRGCs, especially at those with high number of injury and fatality crashes. Enforcement of traffic nearby HRGCs is necessary to prevent vehicles from overtaking of standing vehicles.

Model crash frequency at highway–railroad grade crossings using negative binomial regression

Despite the fact that traffic collisions at highway–railroad grade crossings (HRGXs) are rare events, the impact of HRGX crashes is nevertheless more severe than highway crashes. Empirical studies show that traffic collisions at HRGXs are mainly attributed to railway-related and/or highway-related characteristics, particularly drivers’ abnormal behavior, driving around, or through an HRGX. These factors have different effects on crash likelihood (i.e., the number of traffic collisions or crash frequency) at an HRGX. To explore the causal relationship between crash frequency and the factors related to railroad and highway systems, we used a negative binomial regression model to identify the factors that are statistically significantly associated with traffic collisions at HRGXs, and conducted relevant sensitivity analyses to investigate the marginal effect of daily highway traffic on changes in crash frequency. The empirical study shows that the number of daily trains, the number of tracks, highway separation, annual averaged daily traffic (AADT), and crossing length had statistically significant effects on the mean number of traffic collisions (all p-values ≤ 0.0487). Further, the marginal effect of the AADT on the change of crash frequency indicates that crash likelihood monotonically increases with the increase of AADT.

Study of Driver’s Behavior at Passive Railroad-Highway Grade Crossings

Railway highway grade crossing safety has always been a concern for railroads, state DOTs, and the driving population. This paper presents an overview of drivers' behavior at different passive warning sign systems present at a selected number of Kansas railroad-highway grade crossings. Emphasis in this study was on drivers' stopping behavior at the STOP signs, as that has been a major concern of Kansas DOT (KDOT). A field study was conducted on nine grade crossings with selected warning devices to determine driver's approach behavior, particularly stopping behavior at STOP signs. Various statistical analysis and comparisons are done for stopping of heavy trucks, school buses and other vehicles at crossings with both poor and good sight distance on their approaches. Based on the field tests conducted it was found that the majority of drivers did not stop at the STOP signs at the grade crossings. A higher percentage of drivers actually stopped at crossings with poor sight distance on the approach than on approaches with good sight distance. The use of the STOP sign at passive grade crossings has been controversial for several decades. This paper presents a brief history of their use and the controversy. Based on this limited study, the authors recommended that a STOP sign should not be used at grade crossings without a valid engineering study that includes an evaluation of the sight distance.

A latent class modeling approach for identifying vehicle driver injury severity factors at highway-railway crossings

In this paper, we aim to identify the different factors that influence injury severity of highway vehicle occupants, in particular drivers, involved in a vehicle-train collision at highway-railway grade crossings. The commonly used approach to modeling vehicle occupant injury severity is the traditional ordered response model that assumes the effect of various exogenous factors on injury severity to be constant across all accidents. The current research effort attempts to address this issue by applying an innovative latent segmentation based ordered logit model to evaluate the effects of various factors on the injury severity of vehicle drivers. In this model, the highway-railway crossings are assigned probabilistically to different segments based on their attributes with a separate injury severity component for each segment. The validity and strength of the formulated collision consequence model is tested using the US Federal Railroad Administration database which includes inventory data of all the railroad crossings in the US and collision data at these highway railway crossings from 1997 to 2006. The model estimation results clearly highlight the existence of risk segmentation within the affected grade crossing population by the presence of active warning devices, presence of permanent structure near the crossing and roadway type. The key factors influencing injury severity include driver age, time of the accident, presence of snow and/or rain, vehicle role in the crash and motorist action prior to the crash.

Effect of Train Arrival Time on Crash Frequency at Highway–Railroad Grade Crossings

With the use of a general classification regression model, this study investigated the causal relationship between time to train arrival (TTA) and crash frequency at highway–railroad grade crossings. In particular, a stratified structure in the explanatory variables was used to avoid the collinearity problem generally confronted in linear regression models. TTA is a good estimate of rail sight distance and time to collision, and it could be used to predict crash frequency at a grade crossing. A 14-year crash data set accompanied by crossing inventory data including TTAs was collected for the empirical study. Study results indicated that a negative relationship between TTAs and crash frequencies was generally found for all types of trains. Similar causal relationships were also found in various combinations of both crossing attributes and crash characteristics. Sensitivity analysis on the variable combinations was also conducted to investigate the key risk factors that might result in traffic collisions at grade crossings. Policy implications based on the empirical study are discussed, and future research directions are recommended.

Analysis of performance of transitional preemption strategy for traffic signal near at-grade railway grade crossing

Because the prime objective of current preemption methods at signalized intersections near highway-railroad grade crossings is to clear the crossing, secondary objectives such as safe pedestrian crossing and vehicle delay are given less consideration or are ignored completely during the preemption. Under certain circumstances state-of-the-practice traffic signal preemption strategies may cause serious pedestrian safety and efficiency problems at signalized intersections near highway-railroad grade crossings. Recently, an Improved Transition Preemption Strategy (ITPS) that is specifically designed to improve intersection performance and pedestrian safety was developed by Cho and Rilett. Even if the ITPS algorithm improved both the safety and efficiency of signalized intersections near highway-railroad grade crossings, it is impossible to measure the exact benefit of ITPS because the ITPS algorithm was tested only for the worst case scenario at the development stage. For this paper, the ITPS algorithm was tested under normal operating condition, that is, trains were designed to arrive at the crossing randomly during the cycle. Also, the effect of pedestrians was analyzed using a VISSIM simulation model which was calibrated to field conditions. Finally, a benefit/cost analysis was performed. It was concluded that the ITPS algorithm improves both the safety and efficiency of signalized intersections near highway-railroad grade crossings for normal operating condition.

Evaluation of Effectiveness of Stop-Sign Treatment at Highway–Railroad Grade Crossings

The safety benefit of stop-sign treatment employed at passive highway–rail crossings has been a subject of research for many years. The objective of this study is to assess the effectiveness of the stop-sign treatment on crossing safety. Using the Federal Railroad Administration database, the research focused on 26 years of vehicle–train accident history in the United States from 1980 through 2005. A before-and-after and cross-sectional statistical analysis was conducted for 7,394 public highway–railroad grade crossings that were upgraded from cross buck only to stop signs without involvement in other traffic-control devices (TCDs) or automatic countermeasures. The study found that accident rates based on annual accident frequency per 1,000 crossings were significantly higher during the period when crossings were controlled by cross bucks only than when they were controlled by stop signs. Further, this study developed negative binomial accident prediction models, respectively, for paved and unpaved highway–rail grade-crossings that include effect for stop-sign treatment. Based on specific attributes of the current crossbuck-only-controlled crossings, decision makers and traffic engineers can use the models to examine the accident risks at crossings and assess the potential effectiveness of stop-sign treatment.