Systemic Low-Cost Countermeasures for an Unsignalized Intersection Safety Improvement Plan for Virginia - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Systemic Low-Cost Countermeasures for an Unsignalized Intersection Safety Improvement Plan for Virginia write by Cottrell, Jr. (Benjamin H.). This book was released on 2018. Systemic Low-Cost Countermeasures for an Unsignalized Intersection Safety Improvement Plan for Virginia available in PDF, EPUB and Kindle. With more than 80,000 unsignalized intersections in Virginia, determining how and where to focus limited highway safety resources through deployment of low-cost, high-benefit systemic countermeasures is paramount to beginning to reduce the number of fatal and injury crashes at unsignalized intersections in Virginia. The purpose of this study was to develop a safety improvement plan for unsignalized intersections using systemic low-cost countermeasures. The scope of the study focused on unsignalized intersections with stop sign control on the minor approaches. Virginia’s unsignalized intersection crashes over a 5-year period were assessed to determine predominant crash trends and crash types to target for treatment. Three Virginia Department of Transportation (VDOT) databases (crashes, roadway inventory, and traffic counts) were combined for unsignalized intersections. Four focus collision types with the highest frequency of crashes and the greatest potential reduction in crashes were identified from the data: 3-leg angle, 3-leg fixed object off road, 4-leg angle, and 4-leg rear-end. Chi-square automatic interaction detection (CHAID) was used to perform a systemic analysis to identify a group of intersections based on independent variables (roadway inventory and traffic count variables) that were most strongly related to the focus collision types. After the crash assessment was performed, case studies of selected intersections in each group were reviewed to assess the factors that might influence the four focus collision types. A tiered list of countermeasures to deploy was developed based on the literature and input from VDOT staff. The countermeasures were intended to warn of the stop ahead, to make the stop sign and stop location more visible on the minor street, and to warn of the intersection ahead on the major street. The potential for safety improvement measure was used to prioritize the candidate treatment intersections. Before deployment, a study of the intersections conducted by district traffic engineering staff is planned in order to finalize the safety improvement plan. The output of the study is a safety improvement plan to deploy treatments to unsignalized intersections systemically as part of the safety program. The plan can be adjusted based on available funding.
Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections
Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections write by . This book was released on 2009. Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections available in PDF, EPUB and Kindle. "The purpose of this document is to present information on suggested effective, low-cost intersection countermeasures developed using intersection safety research results and input from an intersection safety expert panel. These low-cost countermeasures can be applied to a large number of intersections with a high frequency of crashes using a systematic approach. The net impact of such an approach can produce significant reductions in statewide intersection crashes, fatalities, and serious injuries. Low-cost countermeasures are defined as those ranging from $1,000 to $50,000 per intersection"--Page 4
Safety Performance Functions for Intersections on Highways Maintained by the Virginia Department of Transportation
Safety Performance Functions for Intersections on Highways Maintained by the Virginia Department of Transportation - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Safety Performance Functions for Intersections on Highways Maintained by the Virginia Department of Transportation write by Nicholas J. Garber. This book was released on 2010. Safety Performance Functions for Intersections on Highways Maintained by the Virginia Department of Transportation available in PDF, EPUB and Kindle. In recent years, significant effort and money have been invested through research and implemented safety projects to enhance highway safety in Virginia. However, there is still substantial room for improvement in both crash frequency and severity. As there are limits in the available funds for safety improvements, it is crucial that allocated resources for safety improvement be spent at highway locations that will result in the maximum safety benefits. In addition, intersection crashes play a significant role in the safety conditions in Virginia. For example, crashes at intersections in Virginia for the period 2003 through 2007 account for 43.8% of all crashes and 26% of fatal crashes. Therefore, identifying intersections for safety improvements that will give the highest potential for crash reduction when appropriate safety countermeasures are implemented will have a significant impact on the overall safety performance of roads in Virginia. The Federal Highway Administration (FHWA) has developed a procedure for identifying highway locations that have the highest potential for crash reduction (ITT Corporation, 2008). A critical component of this method is the use of safety performance functions (SPFs) to determine the potential for crash reductions at a location. An SPF is a mathematical relationship (model) between frequency of crashes by severity and the most significant causal factors on a specific highway. Although the SafetyAnalyst User's Manual presents several SPFs for intersections, these were developed using data from Minnesota. FHWA also suggested that if feasible, each state should develop its own SPFs based on crash and traffic volume data from the state, as the SPFs that are based on Minnesota data may not adequately represent the crash characteristics in all states. SPFs for intersections in Virginia were developed using the annual average daily traffic as the most significant causal factor, emulating the SPFs currently suggested by SafetyAnalyst. The SPFs were developed for both total crashes and combined fatal plus injury crashes through generalized linear modeling using a negative binomial distribution. Models were also developed for urban and rural intersections separately, and in order to account for the different topographies in Virginia, SPFs were also developed for three regions: Northern, Western, and Eastern. This report covers Phases I and II of the study, which includes urban and rural intersections maintained by VDOT. Statistical comparisons of the models based on Minnesota data with those based on the Virginia data showed that the specific models developed for Virginia fit the Virginia crash data better. The report recommends that VDOT's Traffic Engineering Division use the SPFs developed for Virginia and the specific regional SPFs suggested in this report to prioritize the locations in need of safety improvement.
Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections
Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections write by . This book was released on 2009. Low-cost Safety Enhancements for Stop-controlled and Signalized Intersections available in PDF, EPUB and Kindle. The purpose of this document is to present information on suggested effective, low-cost intersection countermeasures developed using intersection safety research results and input from an intersection safety expert panel. These low-cost countermeasures can be applied to a large number of intersections with a high frequency of crashes using a systematic approach. The net impact of such an approach can produce significant reductions in statewide intersection crashes, fatalities, and serious injuries. Low-cost countermeasures are defined as those ranging from 1,000 to 50,000 dollars per intersection.
Development of a Safety Evaluation Procedure for Identifying High-risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District
Development of a Safety Evaluation Procedure for Identifying High-risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District - read free eBook in online reader or directly download on the web page. Select files or add your book in reader. Download and read online ebook Development of a Safety Evaluation Procedure for Identifying High-risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District write by Young-Jun Kweon. This book was released on 2007. Development of a Safety Evaluation Procedure for Identifying High-risk Signalized Intersections in the Virginia Department of Transportation's Northern Virginia District available in PDF, EPUB and Kindle. This research was undertaken to develop an evaluation procedure to identify high-risk four-legged signalized intersections in VDOT's Northern Virginia district by traffic movements and times of day. By using the developed procedure, traffic engineers are expected to be able to identify signalized intersections where the traffic crash occurrences under different traffic conditions for different times of day are more frequent than would normally be expected. Using generalized linear models such as negative binomial models, one safety performance function was estimated for each of nine crash population reference groups formed by three traffic crash patterns (crash patterns 1, 4, and 6) and four times of day (A.M. peak, mid day, P.M. peak, and evening off peak). Crash pattern 1 is a same-direction crash (rear-end, sideswipe or angle crash) that occurs after exiting the intersection; crash pattern 4 is a right-angle crash between two adjacent straight-through vehicle movements in the intersection; and crash pattern 6 is an angle or head-on or opposite sideswipe crash between a straight-through vehicle movement and an opposing left-turn vehicle movement in the intersection. The procedure developed in this study is based on the empirical Bayes (EB) method. Additional data do not need to be collected in order to use the EB procedure because all the data required for applying the EB procedure should be obtainable from VDOT's crash database and from Synchro input data that are already available to traffic engineers for traffic signal phase plans. Thus, the EB procedure is cost-effective and readily applicable. For easy application of the EB procedure, an EB spreadsheet was developed using Microsoft Excel, and a users' guide was prepared. These are available from the author upon request.
