Updating RoadHAT : collision diagram builder and HSM elements.

Details

• Creators:
  Tarko, Andrew P. ; Romero, Mario A. ; Thomaz, Jose E. ; Ramos, Jorge ; Sultana, Afia ; Pineda, Raul ; Chen, Erdong
• Corporate Creators:
  Purdue University. Joint Transportation Research Program
• Corporate Contributors:
  Indiana Department of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Collision diagrams
  • Highway safety
  • Traffic safety
  • Collisions
  • road safety management
  • road network screening
  • economic
  • evaluation
  • collision diagram builder
• Publication/ Report Number:
  FHWA/IN/JTRP-2016/11
• Resource Type:
  Tech Report
• Geographical Coverage:
  Indiana
• Corporate Publisher:
  Purdue University. Joint Transportation Research Program
• Abstract:
  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.
  More +
• Format:
  PDF
• Funding:
  SPR-3726
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31629/dot_31629_DS1.pdf
• File Type:
  [PDF - 3.81 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha256:39b4028f1ce81861c014227ebe6f24cf38defdf787e56fefb67f7cbff2fe91a6