Study Details

Study Title: Estimation of bicycle crash modification factors (CMFs) on urban facilities using zero inflated negative binomial models

Authors: Raihan et al.

Publication Date: FEB, 2019

Abstract: The objective of this study was to develop crash modification factors (CMFs) for bicycle crashes for different roadway segment and intersection facility types in urban areas. The study used four years (2011–2014) of crash data from Florida to quantify the safety impacts of roadway and traffic characteristics, bicycle infrastructure, and bicycle activity data on bicycle crashes. A cross-sectional analysis using Generalized Linear Model (GLM) approach with Zero Inflated Negative Binomial (ZINB) distribution was adopted to develop the relevant regression models in this study. Lane width, speed limit, and grass in the median were observed to have positive impacts on reducing bicycle crashes. On the contrary, presence of sidewalk and sidewalk barrier were found to increase the bicycle crash probabilities. Increased bicycle activity was found to reduce the bicycle crash probabilities on segments, while increased bicycle activity resulted in higher bicycle crash probabilities at intersections. Bus stops were found to increase the bicycle crash probabilities at intersections, whereas, protected signal control had a positive impact on bicycle safety. This research provides a greater insight into how various characteristics affect bicycle safety, a topic that is seldom considered by researchers and practitioners.

Study Citation: Raihan, M.A., P. Alluri, W. Wu, and A. Gan. "Estimation of bicycle crash modification factors (CMFs) on urban facilities using zero inflated negative binomial models". Accident Analysis and Prevention, Vol. 123, (2019), pp. 303-313.

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Bicyclists

Countermeasure: Install sidewalk barrier

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.83 -83 2 Stars Vehicle/bicycle All Not specified Urban

Category:Intersection traffic control

Countermeasure: Provide protected left-turn phase

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.69 31 3 Stars Vehicle/bicycle All Not specified Urban

Category:Pedestrians

Countermeasure: Install sidewalk

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.53 -53 3 Stars Vehicle/bicycle All Not specified Urban
3.09 -209 3 Stars Vehicle/bicycle All Not specified Urban

Category:Roadside

Countermeasure: Change median from paved to grass

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.72 28 3 Stars Vehicle/bicycle All Not specified Urban
0.7 30 3 Stars Vehicle/bicycle All Not specified Urban

Countermeasure: Change paved median to raised traffic separator

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.27 -27 3 Stars Vehicle/bicycle All Not specified Urban

Category:Roadway

Countermeasure: Change lane width from X to Y (in feet)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
CMF Equation CRF Equation 3 Stars Vehicle/bicycle All Not specified Urban
CMF Equation CRF Equation 3 Stars Vehicle/bicycle All Not specified Urban

Countermeasure: Reduce lane width from 12 ft to less than 12 ft

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.72 -72 2 Stars Vehicle/bicycle All Not specified Urban
1.25 -25 3 Stars Vehicle/bicycle All Not specified Urban

Category:Shoulder treatments

Countermeasure: Convert from paved shoulder to other

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.48 52 2 Stars Vehicle/bicycle All Not specified Urban

Countermeasure: Convert paved shoulder to curb and gutter

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.21 -21 3 Stars Vehicle/bicycle All Not specified Urban

Category:Speed management

Countermeasure: Change posted speed limit from X MPH to Y MPH

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
CMF Equation CRF Equation 2 Stars Vehicle/bicycle All Not specified Urban
CMF Equation CRF Equation 3 Stars Vehicle/bicycle All Not specified Urban
CMF Equation CRF Equation 3 Stars Vehicle/bicycle All Not specified Urban
CMF Equation CRF Equation 3 Stars Vehicle/bicycle All Not specified Urban