Download or read book Developing Crash Modification Factors for Variable Speed Limits written by Raul Avelar and published by . This book was released on 2021 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study was to perform rigorous safety effectiveness evaluations of variable speed limit (VSL) implementation on freeway corridors. To accomplish this objective, the research team compiled safety data from Virginia, Wyoming, and Georgia and used an interrupted time series study design (with a comparison group for Georgia). The team analyzed data using logistic and negative binomial generalized estimating equations models. The results from Wyoming and Georgia produced evidence of significant reductions in several types of crashes. The research team found total crash reductions of 34.4 and 29.2 percent associated with VSL installations in Wyoming and Georgia, respectively. The economic evaluation for these two States generally indicated larger benefits than costs. For Georgia, the estimated benefit–cost (B/C) ratio was 40.38. The economic analysis for Wyoming yielded a more modest B/C ratio of 9.05, though still indicating benefits outweighing VSL installation costs. Results from Virginia were inconclusive as the analysis found no statistical evidence of a change in overall safety. The inconclusiveness of these results is possibly due to the sample size of the after period, the small amount of time the system was active, and the manner in which the VSL was used in the corridor for enhancing safety during adverse weather conditions.
Download or read book Developing Crash Modification Factors for Variable Speed Limits written by and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This document is a technical summary of the Federal Highway Administration Report Developing Crash Modification Factors for Variable Speed Limits (FHWA-HRT-21-053) (Avelar et al. 2021).
Download or read book Developing Crash Modification Factors for Variable Speed written by and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Guide to Developing Quality Crash Modification Factors written by Frank Gross and published by . This book was released on 2010 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Developing Crash Modification Factors for Adaptive Signal Control Technologies written by and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Developing crash modification factors for high friction surface treatments written by David K. Merritt and published by . This book was released on 2020 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crash Modification Factors in Practice written by and published by . This book was released on 2013 with total page 27 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Accident Modification Factors for Traffic Engineering and ITS Improvements written by David L. Harkey and published by . This book was released on 2008 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: TRB¿s National Cooperative Highway Research Program (NCHRP) Report 617: Accident Modification Factors for Traffic Engineering and ITS Improvements explores the development of accident modification factors (AMFs) for traffic engineering and intelligent transportation system improvements. AMFs, also known as crash reduction factors, are designed to provide a simple and quick way of estimating the safety impacts of various types of engineering improvements, encompassing the areas of signing, alignment, channelization, and other traffic engineering solutions.
Download or read book Developing crash modification factors for high friction surface treatments written by David K. Merritt and published by . This book was released on 2020 with total page 37 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Guidelines for the Development and Application of Crash Modification Factors written by Daniel Lance Carter and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Crash modification factors (CMF) provide transportation professionals with the kind of quantitative information they need to make decisions on where best to invest limited safety funds.
Download or read book Developing Crash Modification Factors for Operational Parameters on Urban Freeways written by Eugene Vida Maina and published by . This book was released on 2013 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies have shown that, roadway safety has become an intensively investigated topic with the objective of improved understanding of the factors that cause crashes to occur. However, it has been shown that as traffic volumes continue to increase across the United States, 52% of drivers feel less safe on the roads today more than they did five years ago and that the American public feels that traffic safety is a serious problem that needs both the government and media to pay more attention to this issue. In response to these public and driver grievances, State and National transportation agencies have been and continue to pursue and understand the causes and solutions that would significantly reduce roadway crash frequencies. At national level, through various and rigorous studies, the American Association of State Highway and Transportation Officials, AASHTO has published the Highway Safety Manual to quantify safety using predictive models and CMFs. Various efforts have been attempted at state level too, for example, Texas DOT has developed an Interim Roadway Safety Design Workbook that describes the relationship between various roadway elements and each element influences roadway safety. In an effort to contribute towards understanding and resolving the factors that influence crash frequencies on roadways, through a thorough literature search. This study realizes that although there has been vast research in this area, no study has explicitly explained why there is variation in crash frequencies on roadways segments with similar physical/geometric features and annual average daily traffic (AADT). Studies suggest that these variations are due to volume changes throughout the day, an effect literature shows that can only be addressed by hourly volumes and not AADT. Driven by these literature conclusions, this dissertation develops crash modification factors (CMFs) for urban freeways by considering level of service (LOS) deterioration due to change in hourly traffic volumes. Here, this study investigates LOS when it deteriorated from A to B, B to C, C to D, D to E and E to F using hourly volume and hourly crash data collected on urban freeway segments, specifically routes US 1, NJ 3 and NJ 21 in the State of New Jersey. Data were collected on 14 miles of urban freeway segments and 1344 hours of traffic volume count and crash data were analyzed for a period of four years, 2008, 2009, 2010, and 2011. Results from this investigation, shows that operational elements have some influence on urban freeway safety. This dissertation shows that as LOS deteriorated from A to B, B to C, C to D, D to E and E to F, the estimated CMFs were 0.673, 1.110, 0.865, 1.452, and 0.370 respectively. These findings concur with those referred to in this dissertation’s literature review findings, which showed that by adding capacity, that is, by reducing congestion initially results in safety improvement that diminishes as congestion increases.
Download or read book Exploration and Development of Crash Modification Factors and Functions for Single and Multiple Treatments written by Juneyoung Park and published by . This book was released on 2015 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, the CMFs and CMFunctions are estimated for various single and combination of treatments for different roadway types (e.g. rural two-lane, rural multi-lane roadways, urban arterials, freeways, etc.) as below: [bullet] Treatments for mainline of roadway: [bullet] adding a thru lane, conversion of 4-lane undivided roadways to 3-lane with two-way left turn lane (TWLTL) [bullet] Treatments for roadway shoulder: [bullet] installing shoulder rumble strips, widening shoulder width, adding bike lanes, changing bike lane width, installing roadside barriers [bullet] Treatments related to roadside features: [bullet] decrease density of driveways, decrease density of roadside poles, increase distance to roadside poles, increase distance to trees Expected contributions of this study are to 1) suggest approaches to estimate more reliable safety effects of multiple treatments, 2) propose methodologies to develop CMFunctions to assess the variation of CMFs with different characteristics among treated sites, and 3) recommend applications of using GNM and MARS to simultaneously consider the interaction impact of more than one variables and nonlinearity of predictors. Finally, potential relevant applications beyond the scope of this research but worth investigation in the future are discussed in this dissertation.
Download or read book Developing Crash Modification Factors for High Friction Surface Treatments written by David K. Merritt and published by . This book was released on 2020 with total page 75 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents results and observations from friction testing of high-friction surface treatments (HFSTs) as part of an FHWA research study, Developing Crash-Modification Factors for High-Friction Surface Treatments. This larger study provides high-quality crash-modification factors and benefit–cost ratios for HFST with calcined bauxite aggregate and recommends materials and specifications for applying HFST to effectively reduce roadway departure crashes. Friction testing was performed to document the friction of the HFST and underlying pavement. For a number of sites, friction testing was performed on the existing pavement surface before HFST installation and on the HFST after installation. In some cases, testing of the pavement leading up to and away from existing HFST sites was used to estimate the friction of the underlying pavement for comparison to HFST friction. To evaluate friction change of HFST over time, friction testing was also performed on several older HFST installations where previous friction data had been collected. All friction testing was performed with a highway friction tester, a continuous fixed-slip measurement device that provides a continuous plot of friction reported in 0.30-meter (1-foot) increments through the section of pavement tested. The advantage of continuous friction measurement is that variations in friction (e.g., through a curve) can be documented. The friction data collected during this research and documented in this report were evaluated for friction change before and after HFST installation, friction change of the HFST and existing pavement over time, and friction change within a curve.
Download or read book Crash Modification Factors in Practice written by and published by . This book was released on 2013 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Crash Modification Factors written by and published by . This book was released on 2013 with total page 2 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crash Modification Factors in Practice written by and published by . This book was released on 2013 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Crash Modification Factors in Practice written by and published by . This book was released on 2013 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:
