Study Details

Study Title: Validation and Application of Highway Safety Manual (Part D) in Florida

Authors: Abdel-Aty et al.

Publication Date: MAY, 2014

Abstract: The Highway Safety Manual (HSM) Part D provides a comprehensive list of the effects of safety treatments (countermeasures). These effects are quantified by crash modification factors (CMF), which are based on compilation from past studies of the effects of various safety treatments. The HSM Part D provides CMFs for treatments applied to roadway segments (e.g., roadside elements, alignment, signs, rumble strips, etc.), intersections (e.g., control), interchanges, special facilities (e.g., highway-rail crossings), and road networks. Thus, an assessment of the applicability of the HSM in Florida is essential. The objectives of this study are (1) to develop CMFs for various treatments in Florida for the same setting (rural/urban), road type, crash type, and severity level, (2) to evaluate the difference between these Florida-specific CMFs and the CMFs in the HSM, and (3) to recommend whether the CMFs in the HSM can be applied to Florida or new Florida-specific CMFs are needed. Different methods of observational study - before-after (B-A) and cross-sectional (C-S) - were used to calculate CMFs for a total of 17 treatments applied to roadway segments, intersections and special facilities. The CMFs calculated using the before-after with comparison-group (C-G) and empirical Bayesian (EB) methods, only the CMF with lower standard error was selected. The methods of calculating CMFs were determined based on the availability of the data and the methods used in the HSM, if the CMFs were provided in the HSM. It was found that Florida-specific CMFs were generally statistically significant, and safety effects represented by the CMFs were intuitive, similar to the CMFs in the HSM. It was also found that Florida-specific CMFs for the treatments not included in the HSM showed significant positive effects in reducing crash frequencies.

Study Citation: Abdel-Aty, M.A., C. Lee, J. Park, J.Wang, M. Abuzwidah, and S. Al-Arifi. "Validation and Application of Highway Safety Manual (Part D) in Florida." Florida Department of Transportation. Tallahassee, Florida. (May 2014).

Related Citations: Park, J., M. Abdel-Aty, J. Lee, and C. Lee. "Developing crash modification functions to assess safety effects of adding bike lanes for urban arterials with different roadway and socio-economic characteristics". Accident Analysis and Prevention, Vol. 74, (2015) pp. 179-191.

Study Report: Download the Study Report Document


CMFs Associated With This Study

Category: Access management

Countermeasure: 10-ft to 100-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.25 75 2 Stars All All Not specified Urban
0.87 13 2 Stars All All Not specified Urban
0.58 42 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 20-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.86 14 2 Stars All All Not specified Urban
0.98 2 2 Stars All All Not specified Urban
0.94 6 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 30-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.73 27 2 Stars All All Not specified Urban
0.94 6 2 Stars All All Not specified Urban
0.89 11 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 40-ft converstion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.63 37 2 Stars All All Not specified Urban
0.95 5 2 Stars All All Not specified Urban
0.84 16 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 50-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.54 46 2 Stars All All Not specified Urban
0.94 6 2 Stars All All Not specified Urban
0.79 21 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 60-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.46 54 2 Stars All All Not specified Urban
0.92 8 2 Stars All All Not specified Urban
0.74 26 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 70-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.39 61 2 Stars All All Not specified Urban
0.91 9 2 Stars All All Not specified Urban
0.7 30 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 80-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.34 66 2 Stars All All Not specified Urban
0.89 11 2 Stars All All Not specified Urban
0.66 34 2 Stars All All Not specified Urban

Countermeasure: 10-ft to 90-ft conversion (median width)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.29 71 2 Stars All All Not specified Urban
0.88 12 2 Stars All All Not specified Urban
0.62 38 2 Stars All All Not specified Urban

Countermeasure: Install raised median

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.81 19 2 Stars All K,A,B,C Not specified Urban
0.74 26 2 Stars All O Not specified Urban
0.32 68 2 Stars Head on All Not specified Urban
0.76 24 2 Stars All K,A,B,C Not specified Rural
0.75 25 2 Stars All O Not specified Rural
0.29 71 2 Stars Head on All Not specified Rural

Category:Advanced technology and ITS

Countermeasure: Convert existing barrier tollbooths to open road tolling (ORT) facility

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.53 47 3 Stars All All Principal Arterial Other Freeways and Expressways Not specified
0.54 46 3 Stars All K,A,B,C Principal Arterial Other Freeways and Expressways Not specified
0.46 54 3 Stars All O Principal Arterial Other Freeways and Expressways Not specified
0.34 66 3 Stars Rear end All Principal Arterial Other Freeways and Expressways Not specified
0.45 55 3 Stars Other All Principal Arterial Other Freeways and Expressways Not specified

Countermeasure: Install red-light cameras

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.76 24 3 Stars Angle,Left turn All Not specified Urban
1.32 -32 3 Stars Rear end All Not specified Urban
0.74 26 3 Stars Angle,Left turn K,A,B,C Not specified Urban
1.41 -41 3 Stars Rear end K,A,B,C Not specified Urban
0.84 16 3 Stars Angle,Left turn All Not specified Urban
1.17 -17 3 Stars Rear end All Not specified Urban
0.87 13 3 Stars Angle,Left turn K,A,B,C Not specified Urban
1.23 -23 3 Stars Rear end K,A,B,C Not specified Urban
0.89 11 3 Stars Angle,Left turn All Not specified Urban
0.99 1 3 Stars Rear end All Not specified Urban
0.92 8 3 Stars Angle,Left turn K,A,B,C Not specified Urban
1.08 -8 3 Stars Rear end K,A,B,C Not specified Urban

Category:Bicyclists

Countermeasure: Install bicycle lanes

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.68 32 2 Stars All All Not specified Urban
0.73 27 2 Stars All K,A,B,C Not specified Urban
0.42 58 2 Stars Vehicle/bicycle All Not specified Urban
0.4 60 2 Stars Vehicle/bicycle K,A,B,C Not specified Urban

Category:Highway lighting

Countermeasure: Install lighting

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.63 37 3 Stars All K,A,B,C All All
0.84 16 3 Stars All O All All
0.68 32 3 Stars All All All All
0.67 33 3 Stars Rear end All All All
0.64 36 3 Stars Angle All All All
0.72 28 3 Stars Single vehicle All All All
0.72 28 3 Stars Other All All All
0.68 32 3 Stars All K,A,B,C Minor Arterial Urban
0.76 24 3 Stars All O Minor Arterial Urban
0.74 26 3 Stars All All Minor Arterial Urban
0.62 38 3 Stars Rear end All Minor Arterial Urban
0.82 18 3 Stars Angle All Minor Arterial Urban
0.63 37 3 Stars Single vehicle All Minor Arterial Urban
0.82 18 3 Stars Other All Minor Arterial Urban
0.89 11 2 Stars All K,A,B,C All All
0.77 23 3 Stars All K,A,B,C Minor Arterial Urban

Category:Intersection geometry

Countermeasure: Conversion of stop-controlled intersection to roundabout

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.38 62 3 Stars All All Not specified Not specified
0.29 71 3 Stars All K,A,B,C Not specified Not specified

Countermeasure: Install left-turn lane

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.73 27 3 Stars All K,A,B,C Not specified Rural
0.69 31 2 Stars All All Not specified Rural
0.64 36 2 Stars All K,A,B,C Not specified Rural

Category:Intersection traffic control

Countermeasure: Install a traffic signal

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.7 30 3 Stars Angle All Not specified Rural
1.95 -95 3 Stars Rear end All Not specified Rural
0.5 50 3 Stars Left turn All Not specified Rural
0.67 33 3 Stars Angle All Not specified Urban
2.26 -126 2 Stars Rear end All Not specified Urban
0.45 55 3 Stars Left turn All Not specified Urban
0.61 39 3 Stars All All Not specified Urban
0.46 54 3 Stars Angle All Not specified Urban
0.71 29 2 Stars Rear end All Not specified Urban
0.66 34 2 Stars Left turn All Not specified Urban

Category:Roadway

Countermeasure: Add a through lane on both directions and a raised median

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.32 68 3 Stars All All Not specified Urban
0.33 67 3 Stars All K,A,B,C Not specified Urban
0.71 29 3 Stars All All Not specified Rural
0.51 49 3 Stars All K,A,B,C Not specified Rural
0.47 53 3 Stars All All Not specified Urban
0.52 48 3 Stars All All Not specified Urban
0.28 72 3 Stars All All Not specified Urban

Countermeasure: Convert 12-foot lanes to 10-foot lanes

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.73 27 2 Stars All All Not specified Rural
0.58 42 3 Stars All All Not specified Rural

Countermeasure: Convert 12-foot lanes to 11-foot lanes

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.85 15 2 Stars All All Not specified Rural
0.76 24 3 Stars All All Not specified Rural

Countermeasure: Convert 12-foot lanes to 9-foot or less

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.62 38 3 Stars All All Not specified Rural
0.44 56 3 Stars All All Not specified Rural

Countermeasure: Convert a TWLTL to a raised median

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.53 47 3 Stars All All Not specified Not specified
0.67 33 3 Stars All K,A,B,C Not specified Not specified
0.27 73 3 Stars Head on All Not specified Not specified

Countermeasure: Road diet (Convert 4-lane undivided road to 2-lanes plus turning lane)

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.56 44 2 Stars All All Principal Arterial Other Urban
0.63 37 2 Stars All K,A,B,C Principal Arterial Other Urban

Category:Shoulder treatments

Countermeasure: Decrease paved right shoulder from 8-ft to X

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
1.16 -16 2 Stars All All Not specified Rural
1.35 -35 2 Stars All All Not specified Rural
1.57 -57 2 Stars All All Not specified Rural
1.82 -82 2 Stars All All Not specified Rural
1.88 -88 2 Stars All K,A,B,C Not specified Rural
1.17 -17 2 Stars All K,A,B,C Not specified Rural
1.37 -37 2 Stars All K,A,B,C Not specified Rural
1.61 -61 2 Stars All K,A,B,C Not specified Rural

Countermeasure: Install shoulder rumble strips

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.712 28.8 3 Stars All All Not specified All
0.808 19.2 2 Stars All K,A,B,C Not specified All
0.503 49.7 2 Stars Run off road All Not specified All
0.67 33 2 Stars Run off road K,A,B,C Not specified All
0.701 29.9 3 Stars All All Not specified Rural
0.768 23.2 4 Stars All All Not specified Rural
0.778 22.2 3 Stars All K,A,B,C Not specified Rural
0.564 43.6 2 Stars Run off road All Not specified Rural
0.678 32.2 2 Stars Run off road K,A,B,C Not specified Rural
0.73 27 2 Stars All All Not specified Rural
0.73 27 2 Stars All All Not specified Rural
0.64 36 3 Stars All K,A,B,C Not specified Rural
0.63 37 2 Stars All K,A,B,C Not specified Rural
0.6 40 2 Stars Run off road All Not specified Rural
0.58 42 2 Stars Run off road All Not specified Rural
0.64 36 2 Stars Run off road K,A,B,C Not specified Rural
0.59 41 2 Stars Run off road K,A,B,C Not specified Rural

Countermeasure: Install shoulder rumble strips and widen shoulder width

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.5 50 2 Stars All All All Rural
0.48 52 2 Stars All All All Rural
0.66 34 2 Stars All K,A,B,C All Rural
0.63 37 2 Stars All K,A,B,C All Rural
0.4 60 2 Stars Run off road All All Rural
0.4 60 2 Stars Run off road All All Rural
0.58 42 2 Stars Run off road K,A,B,C All Rural
0.63 37 2 Stars Run off road K,A,B,C All Rural

Countermeasure: Widen shoulder

CMF CRF(%) Quality Crash Type Crash Severity Roadway Type Area Type
0.82 18 2 Stars All All Not specified Rural
0.66 34 3 Stars All All Not specified Rural
0.68 32 3 Stars All K,A,B,C Not specified Rural
0.51 49 3 Stars All K,A,B,C Not specified Rural
0.68 32 3 Stars Run off road All Not specified Rural
0.6 40 3 Stars Run off road All Not specified Rural
0.39 61 3 Stars Run off road K,A,B,C Not specified Rural