Improved processes for meeting the data requirements for implementing the Highway Safety Manual (HSM) and Safety Analyst in Florida.

PDFTech ReportBDK80-977-37Highway safetyManualsImplementationCalibrationSoftwareData collectionAccident dataUnsignalized intersectionsFloridaFlorida. Dept. of Transportation. Research CenterAlluri, PriyankaSaha, DibakarLiu, KaiyuGan, AlbertFlorida International University. Lehman Center for Transportation ResearchUS Transportation CollectionRecent research in highway safety has focused on the more advanced and statistically proven techniques of highwaysafety analysis. This project focuses on the two most recent safety analysis tools, the Highway Safety Manual (HSM)and SafetyAnalyst. Meeting the data requirements is considered the most challenging task in implementing thesetools.In the case of HSM, many of the data variables needed for deriving the HSM calibration factors are currentlyunavailable in Florida\u2019s roadway characteristics inventory (RCI) database. This project attempts to identify andprioritize influential calibration variables for data collection and to determine the minimum sample sizes to estimatereliable calibration factors. For each facility type included in the HSM, this project applied the random foresttechnique to rank both the required and desired variables based on their importance. The variables were categorizedinto three groups: variables of primary importance; variables of secondary importance; and variables of lesserimportance. The minimum sample sizes to estimate reliable calibration factors for different facility types were alsodetermined. It was found that the minimum sample size of 30-50 sites with at least 100 crashes per year, asrecommended by HSM, is insufficient to achieve the desired accuracy for nearly all facility types.Compared to HSM, SafetyAnalyst has lesser but different data requirements. Two major efforts in applyingSafetyAnalyst involve the conversion of local data into the strict data format required by SafetyAnalyst and thedevelopment of jurisdiction-specific safety performance functions (SPFs). This project developed a softwareprogram to convert the crash and roadway data for Florida\u2019s state roads to \u201cimport\u201d files used by SafetyAnalyst. Inaddition, this project also developed the SPFs for unsignalized intersections to supplement those of other facilitieswhich were developed under a separate project. For demonstration, SafetyAnalyst was applied using Florida\u2019s data toidentify high crash locations. Recommendations for deploying SafetyAnalyst are also provided