In order to minimize the losses resulting from traffic crashes, Indiana developed its road safety management methods before the Highway Safety Manual

and the SafetyAnalyst became available. The considerable cost of replacing the Indiana current practice with the safety management based on the

Highway Capacity Manual prompted the Indiana DOT to continue using its own safety management tools. This study includes two related but distinct

components: (1) comparison of the HSM-based and Indiana methods of safety management, and (2) development of a Collision Diagram Builder (CDB) to

improve current Indiana safety management tools.

This study concluded that the HSM SPFs would need to be calibrated to the Indiana conditions before they could be used. Calibrating the SPFs for, socalled,

base conditions would lead to an insufficient number of roads and, consequently, to estimates that were not trustworthy. This problem is amplified

by the large number of road categories and crash types in HSM (110 categories and 468 crash severity proportions). Furthermore, a re-calibration process

must be repeated over time to keep the SPFs updated to the changes in safety.

An advanced statistical simulation of a safety management system aimed to maximize the total safety benefit was performed. The results indicate that

two best performing criteria: the HSM EPDO-based criterion and the Indiana total cost of crashes criterion are equivalent and they produce the same

results. It is important that the HSM provides guidance as to which screening criteria support which screening objectives because some of the HSM criteria

were found inadequate for maximizing the overall safety benefit. It also was concluded that although the cost of crashes and the Index of Crash Cost and

Frequency used separately proved to be good screening criteria in Indiana, the combined use of these two measures did not deliver any considerable

improvement.

Two differences were found between the HSM and Indiana procedures for evaluating the benefits and costs of safety projects: the infinite period of

analysis and the road capacity constraint on traffic growth. Consequently, Indiana results depend on the capacity constraints while the HSM results

depend on the length of the analysis period. The differences between the two methods were quite limited and they could be fully reconciled if the

capacity constraints was relaxed in the Indiana method and a long analysis period assumed in the HSM method.

A second major component of the study was to improve the current Indiana safety management tool, RoadHAT2, by developing a computer application

facilitating preparation of a so-called collision diagram. These diagrams are an important element of safety audits. They are not used frequently due to a

considerable time required to build collision diagrams. The developed application reduces this time from one or two days to an hour or less. The

application also provides additional tools for analyzing and visualization of crash patterns. A developed CDB User Manual introduces the user to the tool

and provides examples to help the user get familiar with the application.