Causal Factors for Intersection Crashes in Northern Virginia PDF Download
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Author: John Sanders Miller
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 68
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Book Description
Intersection crashes cost the nation more than $40 billion annually, account for more than one-fifth of all highway crash fatalities nationally, and totaled almost 75,000 in the Virginia Department of Transportation's (VDOT) Northern Virginia District for the period 2001 through 2006. Although VDOT maintains several databases containing more than 170 data elements with detailed crash, driver, and roadway attributes, it was not clear to users of these databases how these data elements could be used to identify causal factors for these intersection crashes for two reasons: (1) the quality of some of the data elements was imperfect, and (2) and random variation is inherent in crashes. This study developed an approach to address these two issues. To address the first issue, the completeness and accuracy of the 179 data elements that comprise the VDOT CRASHDATA database were assessed. For the 76 data elements for which the quality of the data was imperfect, eight rules for using these elements were developed. The rules indicate which data elements should be used in certain circumstances; which data elements are incomplete; and how to manipulate the data for certain applications. To address the second issue, classification trees and crash estimation models (CEMs) were developed. The trees showed that specific causal factors, such as the approach alignment or surface condition, successfully indicate whether a given crash was a rear-end or angle crash. By extension, the trees suggested that intersection crashes were not purely random. Accordingly, it was feasible to develop CEMs that for 17 intersection classes predicted the number of crashes for a 1-year period for four crash types: rear-end, angle, injury, and total. The 68 CEMs showed deviance-based pseudo R-square values between 0.07 and 0.74, suggesting that the causal factors explained some, but not all, of the variation in intersection crashes. The CEMs varied by intersection class. Two actions with regard to crash data analysis may be taken as detailed in this report. First, the eight crash data quality rules developed in this study should be considered for use on a case-by-case basis for studies requiring intersection crash data. Second, when they are collected at the crash scene, the variables that successfully classified rear-end and angle crashes may be given increased attention such that every effort is made to ensure these data elements are accurately recorded.
Author: John Sanders Miller
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 68
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Book Description
Intersection crashes cost the nation more than $40 billion annually, account for more than one-fifth of all highway crash fatalities nationally, and totaled almost 75,000 in the Virginia Department of Transportation's (VDOT) Northern Virginia District for the period 2001 through 2006. Although VDOT maintains several databases containing more than 170 data elements with detailed crash, driver, and roadway attributes, it was not clear to users of these databases how these data elements could be used to identify causal factors for these intersection crashes for two reasons: (1) the quality of some of the data elements was imperfect, and (2) and random variation is inherent in crashes. This study developed an approach to address these two issues. To address the first issue, the completeness and accuracy of the 179 data elements that comprise the VDOT CRASHDATA database were assessed. For the 76 data elements for which the quality of the data was imperfect, eight rules for using these elements were developed. The rules indicate which data elements should be used in certain circumstances; which data elements are incomplete; and how to manipulate the data for certain applications. To address the second issue, classification trees and crash estimation models (CEMs) were developed. The trees showed that specific causal factors, such as the approach alignment or surface condition, successfully indicate whether a given crash was a rear-end or angle crash. By extension, the trees suggested that intersection crashes were not purely random. Accordingly, it was feasible to develop CEMs that for 17 intersection classes predicted the number of crashes for a 1-year period for four crash types: rear-end, angle, injury, and total. The 68 CEMs showed deviance-based pseudo R-square values between 0.07 and 0.74, suggesting that the causal factors explained some, but not all, of the variation in intersection crashes. The CEMs varied by intersection class. Two actions with regard to crash data analysis may be taken as detailed in this report. First, the eight crash data quality rules developed in this study should be considered for use on a case-by-case basis for studies requiring intersection crash data. Second, when they are collected at the crash scene, the variables that successfully classified rear-end and angle crashes may be given increased attention such that every effort is made to ensure these data elements are accurately recorded.
Author: Nicholas J. Garber
Publisher:
ISBN:
Category : Roads
Languages : en
Pages : 68
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Book Description
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.
Author:
Publisher: AASHTO
ISBN: 1560512717
Category : CD-ROMS.
Languages : en
Pages : 142
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Book Description
Author: Lee August Rodegerdts
Publisher: Transportation Research Board
ISBN: 0309155118
Category : Technology & Engineering
Languages : en
Pages : 407
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Book Description
TRB's National Cooperative Highway Research Program (NCHRP) Report 672: Roundabouts: An Informational Guide - Second Edition explores the planning, design, construction, maintenance, and operation of roundabouts. The report also addresses issues that may be useful in helping to explain the trade-offs associated with roundabouts. This report updates the U.S. Federal Highway Administration's Roundabouts: An Informational Guide, based on experience gained in the United States since that guide was published in 2000.
Author: Jonathan Frank Antin
Publisher: Transportation Research Board
ISBN: 0309128951
Category : Transportation
Languages : en
Pages : 43
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Book Description
This report from the second Strategic Highway Research Program (SHRP 2), which is administered by the Transportation Research Board of the National Academies, provides a summary of the key aspects of the planning effort supporting the SHRP 2 Naturalistic Driving Study. The study will collect data—on the order of 1 petabyte (1,000 terabytes)—on “naturalistic,” or real-world, driving behavior over a two-year period beginning in fall 2010. The objective of the study is to reduce traffic injuries and fatalities by finding ways to prevent collisions and reduce their severity.
Author:
Publisher:
ISBN:
Category : Automobiles
Languages : en
Pages : 150
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Book Description
Author: United States. Congress. House
Publisher:
ISBN:
Category : United States
Languages : en
Pages : 2064
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Book Description
Author: ITE (Institute of Transportation Engineers)
Publisher: John Wiley & Sons
ISBN: 1118762304
Category : Technology & Engineering
Languages : en
Pages : 688
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Book Description
Get a complete look into modern traffic engineering solutions Traffic Engineering Handbook, Seventh Edition is a newly revised text that builds upon the reputation as the go-to source of essential traffic engineering solutions that this book has maintained for the past 70 years. The updated content reflects changes in key industry standards, and shines a spotlight on the needs of all users, the design of context-sensitive roadways, and the development of more sustainable transportation solutions. Additionally, this resource features a new organizational structure that promotes a more functionally-driven, multimodal approach to planning, designing, and implementing transportation solutions. A branch of civil engineering, traffic engineering concerns the safe and efficient movement of people and goods along roadways. Traffic flow, road geometry, sidewalks, crosswalks, cycle facilities, shared lane markings, traffic signs, traffic lights, and more—all of these elements must be considered when designing public and private sector transportation solutions. Explore the fundamental concepts of traffic engineering as they relate to operation, design, and management Access updated content that reflects changes in key industry-leading resources, such as the Highway Capacity Manual (HCM), Manual on Uniform Traffic Control Devices (MUTCD), AASSHTO Policy on Geometric Design, Highway Safety Manual (HSM), and Americans with Disabilities Act Understand the current state of the traffic engineering field Leverage revised information that homes in on the key topics most relevant to traffic engineering in today's world, such as context-sensitive roadways and sustainable transportation solutions Traffic Engineering Handbook, Seventh Edition is an essential text for public and private sector transportation practitioners, transportation decision makers, public officials, and even upper-level undergraduate and graduate students who are studying transportation engineering.
Author: Kay Fitzpatrick
Publisher: Transportation Research Board
ISBN: 9780309066242
Category : Transportation
Languages : en
Pages : 176
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Book Description
Author: Nicholas J. Garber
Publisher:
ISBN:
Category : Pedestrian accidents
Languages : en
Pages : 56
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Book Description
Although motor vehicle traffic volume continues to increase, recent studies have shown that in most cities about 90 percent of all internal trips within the central business district are walking trips. Additionally, those rural areas experiencing high growth rates are also comending with increases in pedestrian traffic. As pedestrian traffic grows, and the inevitable conflicts between pedestrians and motorists become more frequent, it is axiomatic that the level of risk, particularly for the pedestrians, increases as well. Between 1990 and 1994, pedestrian deaths accounted for 10.1 to 12.5 percent of all traffic fatalities in Virginia. This figure suggests that pedestrian safety improvement can be a promising candidate for the attention of state safety program officials, and that innovative countermeasures should be reviewed. This study was initiated to determine the traffic and geometric characteristics that significantly affect the safety of different classifications of pedestrians as a first step in the identification of potentially effective countermeasures for reducing pedestrian deaths and injuries resulting from crashes with motor vehicles. Data for this project were obtained from police accident reports involving pedestrian crashes over a 3-year period (1988 through 1990). The data were analyzed using inferential statistics to determine the significant characteristics of pedestrian/motor vehicle crashes. The results indicate that age of the pedestrian, location of the crash, type of facility, the use of alcohol, and type of traffic control at the site have significant impact on the risk of pedestrian involvement and the likely severity of injury in motor vehicle crashes. Also, younger pedestrians are more likely to be involved in crashes than older pedestrians, and within city limits, pedestrian involvement rates are significantly higher within roadway sections that lie between the stop line at an intersection and a distance 150 ft. from the stop line.
