Article
Ergonomics
Zihe Zhang, Jun Liu, Xiaobing Li, Xing Fu, Chenxuan Yang, Steven Jones
Summary: Safety Performance Functions (SPFs) are used to predict the number of crashes on highways based on site characteristics. Traditional approaches assume that the relationships between safety performance and observed factors are stationary, but there may be unobserved factors that significantly affect roadway safety. This study uses a spatial modeling approach to incorporate spatial heterogeneity into SPF model estimation.
ACCIDENT ANALYSIS AND PREVENTION
(2023)
Article
Ergonomics
Joshua Stipancic, Paul G. St-Aubin, Bismarck Ledezma-Navarro, Aurelie Labbe, Nicolas Saunier, Luis Miranda-Moreno
Summary: This study evaluates the impact of stop signs on safety, proposes the Intersection Exposure Group (IEG) indicator to classify pedestrian-vehicle interactions, and finds that stop signs significantly reduce vehicle speeds but do not show a significant relationship with vehicle-pedestrian interactions.
JOURNAL OF SAFETY RESEARCH
(2021)
Article
Ergonomics
Amin Mohammadnazar, A. Latif Patwary, Nastaran Moradloo, Ramin Arvin, Asad J. Khattak
Summary: Approximately 40% of motor vehicle crashes in the US are related to intersections. Safety Performance Functions (SPFs), which are vital elements in predictive methods used in the Highway Safety Manual, currently do not explicitly address driving behavior factors. This study demonstrates the incorporation of driving volatility measures in the development of SPFs, resulting in improved model accuracy and performance.
ACCIDENT ANALYSIS AND PREVENTION
(2022)
Article
Engineering, Civil
Anthony Ingle, Timothy J. Gates
Summary: Research shows that offset-T intersections in rural areas have a higher crash rate compared to conventional four-leg intersections, with more single vehicle and rear-end crashes occurring at offset-T intersections and fewer angle crashes due to the elimination of direct crossing maneuvers.
TRANSPORTATION RESEARCH RECORD
(2021)
Article
Ergonomics
Vikash V. Gayah, Eric T. Donnell
Summary: The relationship between expected crash frequency and traffic volume is non-linear, with a proposed alternative functional form allowing for different elasticities within different traffic volume ranges. The new model, applied to two-lane rural roadways in Pennsylvania, offers improved fit and predictive performance compared to traditional and Hoerl functional forms, potentially for future SPF development.
ACCIDENT ANALYSIS AND PREVENTION
(2021)
Article
Ergonomics
Bismarck Navarro, Luis Miranda-Moreno, Nicolas Saunier, Aurelie Labbe, Ting Fu
Summary: This study investigated the safety effectiveness of converting minor-approach-only stop intersections to all-way-stops, showing that the conversion significantly decreased vehicle speed and increased post-encroachment time.
ACCIDENT ANALYSIS AND PREVENTION
(2022)
Article
Engineering, Civil
Anthony Ingle, Timothy J. Gates
Summary: This study evaluates the safety performance of rural road intersections and finds that installing a combined intersection approach and increasing the radius of curvature along the curved segment at these intersections can reduce crash occurrence.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Ergonomics
Chenhui Liu, Wei Zhang
Summary: This study explores driver behaviors at AWSC intersections using naturalistic driving data. The findings show that only 20.2% of drivers make a complete stop at AWSC intersections. Factors such as age, vehicle type, intersection geometry, maneuver, and time of day influence stop sign running decisions. The study highlights the importance of identifying high-risk drivers and intersections to formulate effective measures to deter stop sign running.
JOURNAL OF SAFETY RESEARCH
(2022)
Article
Engineering, Civil
Anthony Ingle, Timothy J. Gates
Summary: This study evaluated the safety influence of intersection skew angle on rural two-lane, two-way facilities using crash data from ten years. The results showed that both three-leg and four-leg intersections had an initially increasing trend of crash rates followed by a decreasing trend as the skew angle increased. The best model to describe the relationship between skew angle and crash occurrence was found to be a categorical model using discrete skew angle ranges.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Engineering, Industrial
Mehmet Baran Ulak, Ayberk Kocatepe, Anil Yazici, Eren Erman Ozguven, Ashutosh Kumar
Summary: Despite the decrease in crashes and fatalities in the U.S. since 1990, pedestrian crashes have been on the rise, prompting initiatives to address pedestrian safety concerns. However, guidelines are limited by the lack of pedestrian data, highlighting the need to quantify safety of pedestrian facilities. This study proposes a safety index for public transportation bus stops to assess pedestrian safety and identify high-risk locations proactively.
Article
Engineering, Civil
Sherif M. Gaweesh, Irfan U. Ahmed, Mohamed M. Ahmed, Shaun S. Wulff
Summary: Truck crashes, especially those involving HAZMAT shipments, in Wyoming are a significant issue. The study found that factors such as vehicle miles traveled, road geometry characteristics, and truck percentage are associated with HAZMAT truck crashes. Traditional and non-traditional countermeasures were proposed to reduce the frequency and severity of these accidents.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Green & Sustainable Science & Technology
Xiamei Wen, Liping Fu, Ting Fu, Jessica Keung, Ming Zhong
Summary: Understanding driver behaviors at stop-controlled intersections is critical for urban traffic system management, smart infrastructure, and CAV. Past studies have been limited by lack of data, but a new methodology using computer-vision data and clustering techniques can classify behaviors and analyze safety impacts. The results suggest potential application for safety measures and risk analysis at stop-controlled intersections.
Article
Engineering, Civil
Simanta Barman, Michael W. Levin
Summary: This study examines the performance of different variations of MP signal timing policies in realistic scenarios and finds that MP control strategies generally outperform current signal control. The findings suggest that most of the claimed performance benefits of MP policies can still be achieved in real-life traffic conditions.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Ergonomics
Dingming Qin, Xuesong Wang, Omar Hassanin, Salvatore Cafiso, Xiangbin Wu
Summary: This study investigates the impact of intersection angle, speed, and crossing distance on the intersection crossing maneuver of automated vehicles (AVs). It proposes the minimum required parameters for the departure sight triangle and identifies the significant influence of intersection angle on the detection angle range.
ACCIDENT ANALYSIS AND PREVENTION
(2022)
Article
Ergonomics
Naveen Eluru, Vikash V. Gayah
Summary: This note proposes a flexible approach for estimating Safety Performance Functions (SPFs) by accounting for variations in traffic volume impact. The proposed approach improves on a previous method by offering more flexibility in model structure and better performance in model estimation, parameter significance testing, and accommodating random parameters. The note also suggests potential avenues for future research.
ACCIDENT ANALYSIS AND PREVENTION
(2022)
Article
Engineering, Civil
Kay Fitzpatrick, Subasish Das, Timothy Gates, Karen K. Dixon, Eun Sug Park
Summary: The NCHRP Project 17-76 investigated factors affecting operating speed and safety on urban/suburban streets, leading to the development of the SLS-Procedure and SLS-Tool to assist engineers in setting speed limits more effectively.
TRANSPORTATION RESEARCH RECORD
(2021)
Article
Engineering, Civil
Fatemeh Fakhrmoosavi, Ramin Saedi, Farish Jazlan, Ali Zockaie, Mehrnaz Ghamami, Timothy J. Gates, Peter T. Savolainen
Summary: Snow removal activities by roadway agencies aim to improve winter mobility and safety. Studies have shown that green warning lights can enhance the visibility of snowplows, and adding green lights with a single flash pattern to amber warning lights can improve conspicuity while keeping glare at an acceptable level compared to configurations using only amber.
TRANSPORTATION RESEARCH RECORD
(2021)
Article
Engineering, Civil
Megat-Usamah Megat-Johari, Nusayba Megat-Johari, Peter T. Savolainen, Timothy J. Gates, Eva Kassens-Noor
Summary: The study assessed the relationship between traffic crashes and the frequency of safety messages displayed on dynamic message signs (DMS). It found that locations with more frequent messages related to speeding or tailgating had significantly fewer speeding-related crashes, while marginal declines in nighttime crashes were observed near messages related to impaired driving. Methodological concerns in the analysis of such data were highlighted, and field research is recommended to further investigate potential impacts on individual driving behavior.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Engineering, Civil
Md Shakir Mahmud, Matthew Motz, Travis Holpuch, Jordan Hankin, Anthony J. Ingle, Timothy J. Gates, Peter T. Savolainen
Summary: A study conducted at freeway interchange ramps in Michigan showed that a dynamic speed feedback sign (DSFS) can effectively slow down driver speeds when entering curves and improve brake response, with the best results achieved when the DSFS is positioned at the point of curvature. The study also found that DSFS is most effective during daytime off-peak periods.
TRANSPORTATION RESEARCH RECORD
(2021)
Article
Engineering, Civil
Anthony Ingle, Timothy J. Gates
Summary: This study evaluates the safety performance of rural road intersections and finds that installing a combined intersection approach and increasing the radius of curvature along the curved segment at these intersections can reduce crash occurrence.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Engineering, Civil
Md Shakir Mahmud, Nischal Gupta, Babak Safaei, Hisham Jashami, Timothy J. Gates, Peter T. Savolainen, Eva Kassens-Noor
Summary: This study examines the impact of speed limit increases on free-flow travel speeds on rural highways in Michigan. The results show that locations where the speed limits were raised experienced increases in travel speeds, while control sites experienced marginal changes. Significant differences were observed across quantiles and site-specific variables.
TRANSPORTATION RESEARCH RECORD
(2021)
Article
Engineering, Civil
Nusayba Megat-Johari, Megat-Usamah Megat-Johari, Peter Savolainen, Timothy Gates, Eva Kassens-Noor
Summary: Move-over laws are intended to enhance the safety of road agency and law enforcement personnel, with research showing drivers are more likely to comply when a police car is present on the shoulder. The type of message displayed, however, has minimal impact on driver behavior, except for targeted move-over messages which led to drivers driving at or below the speed limit. Regardless of the message, drivers are more likely to comply if the roadside vehicle is a police car.
TRANSPORTATION RESEARCH RECORD
(2021)
Article
Engineering, Civil
Meghna Chakraborty, Md Shakir Mahmud, Timothy J. Gates, Subhrajit Sinha
Summary: This study uses linear regularization algorithms to analyze the factors influencing human mobility during the COVID-19 pandemic in the United States, and predicts human mobility based on these factors. The results show that multiple factors have a significant impact on daily trips.
TRANSPORTATION RESEARCH RECORD
(2023)
Article
Engineering, Civil
Md Shakir Mahmud, Anshu Bamney, Megat Usamah Megat Johari, Hisham Jashami, Timothy J. Gates, Peter Tarmo Savolainen
Summary: This study investigated the effectiveness of a dynamic speed feedback sign (DSFS) as a speed reduction measure on horizontal curves of rural highways. The results showed that the DSFS was more effective when installed near the advance curve warning sign, especially at curves with sharper curvature. The continued use of DSFSs on rural horizontal curves is recommended.
TRANSPORTATION RESEARCH RECORD
(2023)
Article
Engineering, Civil
Nischal Gupta, Md Shakir Mahmud, Hisham Jashami, Peter T. Savolainen, Timothy J. Gates
Summary: This study examines the effects of the increase in maximum speed limits on rural freeways in Michigan on traffic speed characteristics. The results consistently show increases in speed metrics, ranging from 1.1 to 3.2 mph depending on the specific metric and data source. Limited spillover effects were observed at sites where speed limits were not changed. Various site-specific characteristics were found to be correlated with speed selection, with differences depending on the data source.
TRANSPORTATION RESEARCH RECORD
(2023)
Article
Engineering, Civil
Anthony Ingle, Timothy J. Gates
Summary: This study evaluated the safety influence of intersection skew angle on rural two-lane, two-way facilities using crash data from ten years. The results showed that both three-leg and four-leg intersections had an initially increasing trend of crash rates followed by a decreasing trend as the skew angle increased. The best model to describe the relationship between skew angle and crash occurrence was found to be a categorical model using discrete skew angle ranges.
TRANSPORTATION RESEARCH RECORD
(2022)
Article
Engineering, Civil
Meghna Chakraborty, Timothy Gates
Summary: Previous research on urban roadway safety has focused on high functional classification roadways, but this study examines low functional classification roadways and finds that speed limits and driveway density have significant impacts on roadway safety performance.
TRANSPORTATION RESEARCH RECORD
(2023)
Article
Engineering, Civil
Ehsan Kamjoo, Ramin Saedi, Ali Zockaie, Mehrnaz Ghamami, Timothy Gates, Alireza Talebpour
Summary: This study investigates the impact of snowplows on car-following behavior and compares car-following models with and without a collision avoidance system. The results show that snowplows significantly affect car-following behavior, while the improvement in behavior from the collision avoidance system is not statistically significant. Additionally, considering driving behavior heterogeneity leads to more accurate prediction of car-following behavior. Developing specific models for winter maintenance operations helps in the development of microsimulation models for adverse weather conditions.
TRANSPORTATION RESEARCH RECORD
(2023)
Article
Engineering, Civil
Md Shakir Mahmud, Timothy J. Gates, Peter Tarmo Savolainen, Babak Safaei
Summary: This research evaluated the effectiveness of dynamic speed feedback signs (DSFSs) as a speed reduction measure at a freeway exit ramp with horizontal curvature. The study found that installing a DSFS near the start of the curve resulted in an average reduction of 3.5 mph in curve entry speeds. The best speed reduction was achieved when the message activated within 250 to 400 ft of the curve. The lateral position and display panel size of the DSFS did not significantly impact curve entry speeds, but adding a yellow sign border enhanced the speed reduction effects.
TRANSPORTATION RESEARCH RECORD
(2023)
Article
Engineering, Civil
Anthony Ingle, Timothy J. Gates
Summary: Research shows that offset-T intersections in rural areas have a higher crash rate compared to conventional four-leg intersections, with more single vehicle and rear-end crashes occurring at offset-T intersections and fewer angle crashes due to the elimination of direct crossing maneuvers.
TRANSPORTATION RESEARCH RECORD
(2021)