A Joint Analysis of Secondary Collisions and Injury Severity Levels Using Structural Equation Models
This study aims to investigate the contributing factors to secondary collisions and the effects of secondary collisions on injury severity levels. Manhattan, which is the most densely populated urban area of New York City, is used as a case study. In Manhattan, about 7.5% of crash events get involved with secondary collisions and as high as 9.3% of those secondary collisions lead to incapacitating and fatal injuries. Structural equation models (SEMs) are proposed to jointly model the presence of secondary collisions and injury severity levels. This study contributes to the literature by fully exploring the determinants of secondary collisions such as speeding, alcohol, fatigue, brake defective, limited view and rain. To assess the temporal effects, the authors use time as a moderator in the proposed SEM framework and results indicate that it is more likely to sustain secondary collisions and severe injuries at night. The parameter estimates of the proposed SEM are further compared with those of the standard probit models which estimate the presence of secondary collisions and injury severity independently. Results show that standard probit models overestimate the safety effects of confounding variables (i.e. variables that can affect both secondary collision occurrence and injury severity) by mixing the direct and indirect effects. In addition, it is found that the standard probit models significantly overestimate the effects of secondary collisions on injury severity propensity by 127.6% for daytime crashes and by 121.2% for nighttime crashes, since the endogeneity of the presence of secondary collisions is ignored in the estimation. Understanding the causes and impacts of secondary collisions can help the transportation agencies and automobile manufacturers develop effective injury prevention countermeasures.
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Supplemental Notes:
- This paper was sponsored by TRB committee ANB20 Standing Committee on Safety Data, Analysis and Evaluation.
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Corporate Authors:
500 Fifth Street, NW
Washington, DC United States 20001 -
Authors:
- Xie, Kun
- Ozbay, Kaan
- Yang, Hong
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Conference:
- Transportation Research Board 95th Annual Meeting
- Location: Washington DC, United States
- Date: 2016-1-10 to 2016-1-14
- Date: 2016
Language
- English
Media Info
- Media Type: Web
- Features: Figures; References; Tables;
- Pagination: 18p
- Monograph Title: TRB 95th Annual Meeting Compendium of Papers
Subject/Index Terms
- TRT Terms: Crash causes; Crash injuries; Fatalities; Injury severity; Periods of the day; Secondary crashes
- Geographic Terms: Manhattan (New York, New York)
- Subject Areas: Highways; Safety and Human Factors; I84: Personal Injuries;
Filing Info
- Accession Number: 01588972
- Record Type: Publication
- Report/Paper Numbers: 16-0206
- Files: TRIS, TRB, ATRI
- Created Date: Jan 29 2016 4:30PM