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Title:

Appropriate Regression Model Types for Intersections in SafetyAnalyst

Accession Number:

01334332

Record Type:

Component

Abstract:

Transportation agencies in the United States have started implementing SafetyAnalyst, highway safety management software. Some agencies have been developing or considering developing safety performance functions (SPFs), a core of the software, using local data to maximize the benefits of the software. With multiple years of data on hand, several regression model types are available for developing the SPFs, yet no reliable guide has been provided in selecting appropriate model types. This study examined 11 model types including 8 panel and 3 cross-sectional models to recommend appropriate model types for intersection SPFs for use with SafetyAnalyst. The models were developed using the data collected from 18,356 intersections in Virginia from 2003 through 2008 and were evaluated using 4 comparison approaches. Appropriate model types for each of the 8 intersection subtypes were found; four all-way stop control subtypes were excluded because of the lack of sufficient observations. In general, a cross-sectional model with summed or averaged crash frequencies was found to underestimate a dispersion parameter that plays a critical role in the empirical Bayes method. Depending on intersection subtype, appropriate model types were found to vary. A panel model with independent correlation and a pooled cross-sectional model were found to be appropriate across all 8 subtypes; if the same model type is desired for the 8 subtypes, these 2 models are recommended for developing SPFs using local data for SafetyAnalyst. Although the conclusions and recommendations were based on sufficient data, they are valid for Virginia and may not be applicable to other states.

Monograph Accession #:

01329018

Report/Paper Numbers:

11-1850

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

Kweon, Young-Jun
Lim, In-Kyu

Pagination:

15p

Publication Date:

2011

Conference:

Transportation Research Board 90th Annual Meeting

Location: Washington DC, United States
Date: 2011-1-23 to 2011-1-27
Sponsors: Transportation Research Board

Media Type:

DVD

Features:

Figures (2) ; References (12) ; Tables (3)

Identifier Terms:

Safety Analyst

Geographic Terms:

Virginia

Subject Areas:

Data and Information Technology; Highways; Safety and Human Factors; I72: Traffic and Transport Planning; I82: Accidents and Transport Infrastructure

Source Data:

Transportation Research Board Annual Meeting 2011 Paper #11-1850

Files:

TRIS, TRB

Created Date:

Feb 17 2011 5:57PM