Study Details

Study Title: Modeling and Evaluating the Safety Impacts of Access Management (AM) Features in the Las Vegas Valley

Authors: Mauga and Kaseko

Publication Date:JAN, 2010

Abstract: This paper presents results of a study that developed statistical models that relate access management (AM) features with traffic safety in midblock sections of street segments. The objective of the study was to evaluate and quantify the impact of the AM features on traffic safety in the midblock sections. It is anticipated that the results of this study will assist local jurisdictions in the Las Vegas valley in the development of new AM policies and programs. Models were calibrated for two main types of median treatments for street segments, namely, raised medians (RM) and two-way-left-turn-lanes (TWLTL). Other AM features considered were signal spacing and the densities of driveways, median openings and unsignalized cross roads. Separate models were developed for the impacts on total crash rates, types of crashes and severity. The study results confirmed the intuitive expectation that these AM features do have significant impact on safety. They show that segments with RM had lower crash rate by 23% compared to segments with TWLTL. The results also show that higher densities of driveways cross roads and median openings results in higher crash rates and severity. For example, for segments with RM, each additional median opening per mile results in a 4.7% increase in the total crash rate. A comparison of these results with pervious similar studies is also made in this paper.

Study Citation: Mauga, T. and Kaseko, M., "Modeling and Evaluating the Safety Impacts of Access Management (AM) Features in the Las Vegas Valley." Transportation Research Record: Journal of the Transportation Research Board 2171, pp. 57-65, 2010


CMFs Associated With This Study

Category: Access management

Countermeasure: Change in driveway density from X to Y driveways per mile

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsAngleAllAllUrban
CMF EquationCRF Equation3 StarsRear endAllAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleA,B,CAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleOAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsAngleAllAllUrban
CMF EquationCRF Equation4 StarsRear endAllAllUrban
CMF EquationCRF Equation3 StarsSideswipeAllAllUrban
CMF EquationCRF Equation4 StarsFixed object,Run off road,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleA,B,CAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleOAllUrban

Countermeasure: Change in median opening density from X to Y median openings

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsAngleAllAllUrban
CMF EquationCRF Equation3 StarsHead onAllAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleA,B,CAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleOAllUrban

Countermeasure: Change in signal spacing from X 1000's feet to Y 1000's feet

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
CMF EquationCRF Equation3 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
CMF EquationCRF Equation3 StarsRear endAllAllUrban
CMF EquationCRF Equation4 StarsSideswipeAllAllUrban
CMF EquationCRF Equation4 StarsFixed object,Run off road,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleOAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsRear endAllAllUrban

Countermeasure: Change in unsignalized cross roads from X to Y unsignalized cross roads per mile

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
CMF EquationCRF Equation4 StarsSideswipeAllAllUrban
CMF EquationCRF Equation3 StarsFixed object,Run off road,Single vehicleAllAllUrban
CMF EquationCRF Equation3 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
CMF EquationCRF Equation4 StarsRear endAllAllUrban
CMF EquationCRF Equation4 StarsSideswipeAllAllUrban
CMF EquationCRF Equation3 StarsHead onAllAllUrban
CMF EquationCRF Equation4 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleA,B,CAllUrban

Countermeasure: Replace TWLTL with raised median

CMF CRF(%)QualityCrash TypeCrash SeverityRoadway TypeArea Type
0.77234 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleAllAllUrban
0.65364 StarsAngleAllAllUrban
0.81194 StarsRear endAllAllUrban
0.79214 StarsSideswipeAllAllUrban
0.53474 StarsHead onAllAll
0.79214 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleA,B,CAllUrban
0.67334 StarsAngle,Fixed object,Head on,Rear end,Run off road,Sideswipe,Single vehicleOAllUrban