This report is intended to identify the data requirements and data availability for AASHTOWare Safety Analyst^TM and the Highway Safety Manual (HSM) by working with both tools. It discusses the potential biases and issues associated with traditional safety analysis methods for selecting projects. The report presents Safety Performance Functions (SPFs) for various classifications of segments in Georgia and compares them against the national SPFs used in AASHTOWare Safety Analyst^TM. It also investigates the influence of actual and estimated traffic data on the fit of the equations, questioning the accuracy and reliability of traffic estimations. The effect of using multiple CMFs is also studied by applying the HSM predictive methodology to two-way two-lane rural roads. Finally, the data requirements, predictive methodology, constraints, and results are compared between AASHTOWare Safety Analyst^TM and the HSM.

The report provides benefits and trade-offs for agencies that are interested in using more rigorous approaches and new safety analysis tools. The main tradeoff for agencies is the requirement of having sufficient data (i.e., comprehensive and accurate) to use the tools. The research also compares results of analyses performed using the HSM versus AASHTOWare Safety Analyst^TM predictive methods, showing that the default SPFs can lead to substantially different predictions. Note that the research was focused on network screening of roadway segments. The report does not provide results for intersections or ramps, and does not assess the other modules in AASHTOWare Safety Analyst^TM.