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Full-Text Articles in Engineering
Safety Impacts Of Signal-Warning Flashers And Speed Control At High-Speed Signalized Intersections, Zifeng Wu, Anuj Sharma, Fred L. Mannering, Shefang Wang
Safety Impacts Of Signal-Warning Flashers And Speed Control At High-Speed Signalized Intersections, Zifeng Wu, Anuj Sharma, Fred L. Mannering, Shefang Wang
Anuj Sharma
For many years, to reduce the crash frequency and severity at high-speed signalized intersections, warning flashers have been used to alert drivers of potential traffic-signal changes. Recently, more aggressive countermeasures at such intersections include a speed-limit reduction in addition to warning flashers. While such speed-control strategies have the potential to further improve the crash-mitigation effectiveness of warning flashers, a rigorous statistical analysis of crash data from such intersections has not been undertaken to date. This paper uses 10-year crash data from 28 intersections in Nebraska (all with intersection approaches having signal-warning flashers; some with no speed-limit reduction, and the others …
Macroscopic Traffic Safety Analysis Based On Trip Generation Characteristics, Chowdhury Siddiqui
Macroscopic Traffic Safety Analysis Based On Trip Generation Characteristics, Chowdhury Siddiqui
Electronic Theses and Dissertations
Recent research has shown that incorporating roadway safety in transportation planning has been considered one of the active approaches to improve safety. Aggregate level analysis for predicting crash frequencies had been contemplated to be an important step in this process. As seen from the previous studies various categories of predictors at macro level (census blocks, traffic analysis zones, census tracts, wards, counties and states) have been exhausted to find appropriate correlation with crashes. This study contributes to this ongoing macro level road safety research by investigating various trip productions and attractions along with roadway characteristics within traffic analysis zones (TAZs) …
Risk Assessment Of Various Median Treatments Of Rural Interstates, Natalie M. Villwock, Nicolas Paul Blond, Andrzej P. Tarko
Risk Assessment Of Various Median Treatments Of Rural Interstates, Natalie M. Villwock, Nicolas Paul Blond, Andrzej P. Tarko
JTRP Technical Reports
This report presents results of a comprehensive study that evaluates the safety impacts of alternative median treatments on rural freeways. Extensive data were obtained from Indiana, Colorado, Illinois, Iowa, Missouri, New York, Ohio, Oregon, Washington, and Wisconsin. The studied median treatments include AASHTO-recommended treatments: depressed medians, depressed medians with high and lowtensioned cable barriers, and flush medians with concrete barriers. Other treatments used in the freeway design were also studied: medians with berms, sloped medians, and depressed medians with berms. Negative binomial models were developed to predict the frequency of crashes in three categories: single vehicle (SV), multiple vehicles same …
Safety Analyses At Signalized Intersections Considering Spatial, Temporal And Site Correlation, Xuesong Wang
Safety Analyses At Signalized Intersections Considering Spatial, Temporal And Site Correlation, Xuesong Wang
Electronic Theses and Dissertations
Statistics show that signalized intersections are among the most dangerous locations of a roadway network. Different approaches including crash frequency and severity models have been used to establish the relationship between crash occurrence and intersection characteristics. In order to model crash occurrence at signalized intersections more efficiently and eventually to better identify the significant factors contributing to crashes, this dissertation investigated the temporal, spatial, and site correlations for total, rear-end, right-angle and left-turn crashes. Using the basic regression model for correlated crash data leads to invalid statistical inference, due to incorrect test statistics and standard errors based on the misspecified …