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Title:

Relationship between Horizontal Curve Density and Safety Performance on Rural Two-Lane Road Segments by Road Jurisdiction and Surface Type

Accession Number:

01764319

Record Type:

Component

Abstract:

This study involved the assessment of the safety impacts associated with horizontal curve density (in terms of number of curves per mile) on rural two-lane state and county road segments in Michigan. Non-animal road segment crashes from 2011 to 2015 were analyzed along with roadway geometry data for greater than 5,556 miles of state highways, 5,890 miles of paved county segments and 2,007 miles of unpaved roads from across Michigan. Several mixed-effects negative binomial regression models with a county- and site-specific random effects combined were generated. The model results indicated a consistent positive association between the density of horizontal curves with design speeds below 55 mph (radius less than 0.191 miles) and crashes across all classes of rural two-lane road segments. Specifically, although the mere presence of a horizontal curve along the segment increases crash occurrence across each of the rural roadway classes analyzed here, the crash occurrence is further increased when the frequency of horizontal curves exceeds 1 per mile for state highways and paved county roads. These results provide further contribution to previous research on the safety effects of horizontal curvature on rural roadways, by suggesting that more frequent changes in horizontal alignment (as indicated by an increasing frequency of curves per mile) increases crash occurrence. This study also further contributes to the limited body of knowledge regarding safety performance on rural secondary roadway segments, including roads under county jurisdictions and unpaved roads.

Supplemental Notes:

This paper was sponsored by TRB committee AKD30 Standing Committee on Low-Volume Roads.

Report/Paper Numbers:

TRBAM-21-03405

Language:

English

Corporate Authors:

Transportation Research Board

Authors:

Chakraborty, Meghna

ORCID 0000-0002-8369-1198

Gates, Timothy J

Pagination:

16p

Publication Date:

2021

Conference:

Transportation Research Board 100th Annual Meeting

Location: Washington DC, United States
Date: 2021-1-5 to 2021-1-29
Sponsors: Transportation Research Board; Transportation Research Board

Media Type:

Digital/other

Features:

Figures; Maps; References; Tables

Geographic Terms:

Michigan

Subject Areas:

Design; Highways; Safety and Human Factors

Source Data:

Transportation Research Board Annual Meeting 2021 Paper #TRBAM-21-03405

Files:

TRIS, TRB, ATRI

Created Date:

Dec 23 2020 11:26AM