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(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.25753 StarsAllAllNot specifiedUrban
0.87133 StarsAllAllNot specifiedUrban
0.58423 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.86143 StarsAllAllNot specifiedUrban
0.9823 StarsAllAllNot specifiedUrban
0.9463 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.73273 StarsAllAllNot specifiedUrban
0.9463 StarsAllAllNot specifiedUrban
0.89112 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.63373 StarsAllAllNot specifiedUrban
0.9553 StarsAllAllNot specifiedUrban
0.84162 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.9463 StarsAllAllNot specifiedUrban
0.54463 StarsAllAllNot specifiedUrban
0.79212 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.46543 StarsAllAllNot specifiedUrban
0.9283 StarsAllAllNot specifiedUrban
0.74263 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.39613 StarsAllAllNot specifiedUrban
0.9193 StarsAllAllNot specifiedUrban
0.7303 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.34663 StarsAllAllNot specifiedUrban
0.89113 StarsAllAllNot specifiedUrban
0.66343 StarsAllAllNot specifiedUrban

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.29713 StarsAllAllNot specifiedUrban
0.88123 StarsAllAllNot specifiedUrban
0.62383 StarsAllAllNot specifiedUrban

Countermeasure: Install raised median

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.32683 StarsHead onAllNot specifiedUrban
0.74263 StarsAllONot specifiedUrban
0.81193 StarsAllK,A,B,CNot specifiedUrban
0.76243 StarsAllK,A,B,CNot specifiedRural
0.75253 StarsAllONot specifiedRural
0.29713 StarsHead onAllNot specifiedRural

Category:Advanced technology and ITS

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.53474 StarsAllAllPrincipal Arterial Other Freeways and ExpresswaysNot specified
0.54464 StarsAllK,A,B,CPrincipal Arterial Other Freeways and ExpresswaysNot specified
0.46544 StarsAllOPrincipal Arterial Other Freeways and ExpresswaysNot specified
0.34664 StarsRear endAllPrincipal Arterial Other Freeways and ExpresswaysNot specified
0.45554 StarsOtherAllPrincipal Arterial Other Freeways and ExpresswaysNot specified

Countermeasure: Install red-light cameras

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
1.17-172 StarsRear endAllNot specifiedUrban
0.76242 StarsAngle,Left turnAllNot specifiedUrban
1.32-322 StarsRear endAllNot specifiedUrban
0.74262 StarsAngle,Left turnK,A,B,CNot specifiedUrban
1.41-412 StarsRear endK,A,B,CNot specifiedUrban
0.84162 StarsAngle,Left turnAllNot specifiedUrban
0.87132 StarsAngle,Left turnK,A,B,CNot specifiedUrban
1.23-232 StarsRear endK,A,B,CNot specifiedUrban
0.89112 StarsAngle,Left turnAllNot specifiedUrban
0.9912 StarsRear endAllNot specifiedUrban
0.9282 StarsAngle,Left turnK,A,B,CNot specifiedUrban
1.08-82 StarsRear endK,A,B,CNot specifiedUrban

Category:Bicyclists

Countermeasure: Install bicycle lanes

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.73272 StarsAllK,A,B,CNot specifiedUrban
0.68322 StarsAllAllNot specifiedUrban
0.42582 StarsVehicle/bicycleAllNot specifiedUrban
0.4602 StarsVehicle/bicycleK,A,B,CNot specifiedUrban

Category:Highway lighting

Countermeasure: Install lighting

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.82183 StarsOtherAllMinor ArterialUrban
0.63374 StarsAllK,A,B,CAllAll
0.84163 StarsAllOAllAll
0.68324 StarsAllAllAllAll
0.67334 StarsRear endAllAllAll
0.64364 StarsAngleAllAllAll
0.72283 StarsSingle vehicleAllAllAll
0.72284 StarsOtherAllAllAll
0.68324 StarsAllK,A,B,CMinor ArterialUrban
0.76244 StarsAllOMinor ArterialUrban
0.74264 StarsAllAllMinor ArterialUrban
0.62384 StarsRear endAllMinor ArterialUrban
0.82184 StarsAngleAllMinor ArterialUrban
0.63374 StarsSingle vehicleAllMinor ArterialUrban
0.89113 StarsAllK,A,B,CAllAll
0.77234 StarsAllK,A,B,CMinor ArterialUrban

Category:Intersection geometry

Countermeasure: Conversion of stop-controlled intersection to roundabout

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.38623 StarsAllAllNot specifiedNot specified
0.29713 StarsAllK,A,B,CNot specifiedNot specified

Countermeasure: Install left-turn lane

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.73273 StarsAllK,A,B,CNot specifiedRural
0.69312 StarsAllAllNot specifiedRural
0.64362 StarsAllK,A,B,CNot specifiedRural

Category:Intersection traffic control

Countermeasure: Install a traffic signal

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.61394 StarsAllAllNot specifiedUrban
0.46544 StarsAngleAllNot specifiedUrban
0.71292 StarsRear endAllNot specifiedUrban
0.66342 StarsLeft turnAllNot specifiedUrban
1.95-953 StarsRear endAllNot specifiedRural
0.5504 StarsLeft turnAllNot specifiedRural
0.67334 StarsAngleAllNot specifiedUrban
2.26-1262 StarsRear endAllNot specifiedUrban
0.45554 StarsLeft turnAllNot specifiedUrban
0.7303 StarsAngleAllNot specifiedRural

Category:Roadway

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.47531 StarAllAllNot specifiedUrban
0.52481 StarAllAllNot specifiedUrban
0.28721 StarAllAllNot specifiedUrban
0.32684 StarsAllAllNot specifiedUrban
0.33674 StarsAllK,A,B,CNot specifiedUrban
0.71294 StarsAllAllNot specifiedRural
0.51494 StarsAllK,A,B,CNot specifiedRural

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.58423 StarsAllAllNot specifiedRural
0.73272 StarsAllAllNot specifiedRural

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.76243 StarsAllAllNot specifiedRural
0.85152 StarsAllAllNot specifiedRural

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.44563 StarsAllAllNot specifiedRural
0.62382 StarsAllAllNot specifiedRural

Countermeasure: Convert a TWLTL to a raised median

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.67332 StarsAllK,A,B,CNot specifiedNot specified
0.53472 StarsAllAllNot specifiedNot specified
0.27732 StarsHead onAllNot specifiedNot specified

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.56443 StarsAllAllPrincipal Arterial OtherUrban
0.63373 StarsAllK,A,B,CPrincipal Arterial OtherUrban

Category:Shoulder treatments

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

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
1.16-163 StarsAllAllNot specifiedRural
1.35-353 StarsAllAllNot specifiedRural
1.57-573 StarsAllAllNot specifiedRural
1.82-823 StarsAllAllNot specifiedRural
1.88-883 StarsAllK,A,B,CNot specifiedRural
1.17-173 StarsAllK,A,B,CNot specifiedRural
1.37-373 StarsAllK,A,B,CNot specifiedRural
1.61-613 StarsAllK,A,B,CNot specifiedRural

Countermeasure: Install shoulder rumble strips

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.71228.83 StarsAllAllNot specifiedAll
0.80819.22 StarsAllK,A,B,CNot specifiedAll
0.50349.72 StarsRun off roadAllNot specifiedAll
0.67332 StarsRun off roadK,A,B,CNot specifiedAll
0.70129.93 StarsAllAllNot specifiedRural
0.76823.24 StarsAllAllNot specifiedRural
0.77822.23 StarsAllK,A,B,CNot specifiedRural
0.56443.62 StarsRun off roadAllNot specifiedRural
0.67832.22 StarsRun off roadK,A,B,CNot specifiedRural
0.73272 StarsAllAllNot specifiedRural
0.73272 StarsAllAllNot specifiedRural
0.64364 StarsAllK,A,B,CNot specifiedRural
0.63372 StarsAllK,A,B,CNot specifiedRural
0.6402 StarsRun off roadAllNot specifiedRural
0.58422 StarsRun off roadAllNot specifiedRural
0.64362 StarsRun off roadK,A,B,CNot specifiedRural
0.59412 StarsRun off roadK,A,B,CNot specifiedRural

Countermeasure: Install shoulder rumble strips and widen shoulder width

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.5502 StarsAllAllAllRural
0.48522 StarsAllAllAllRural
0.66342 StarsAllK,A,B,CAllRural
0.63372 StarsAllK,A,B,CAllRural
0.4602 StarsRun off roadAllAllRural
0.4602 StarsRun off roadAllAllRural
0.58422 StarsRun off roadK,A,B,CAllRural
0.63372 StarsRun off roadK,A,B,CAllRural

Countermeasure: Widen shoulder

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.82183 StarsAllAllNot specifiedRural
0.66344 StarsAllAllNot specifiedRural
0.68324 StarsAllK,A,B,CNot specifiedRural
0.51494 StarsAllK,A,B,CNot specifiedRural
0.68324 StarsRun off roadAllNot specifiedRural
0.6404 StarsRun off roadAllNot specifiedRural
0.39614 StarsRun off roadK,A,B,CNot specifiedRural