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Transportation Performance Management


Transportation Asset Management Case Studies
HERS-ST: The Oregon Experience

Where is ODOT Today?

In Oregon, HERS has proven its value as a transportation planning tool. The Oregon version of HERS was used to support the needs analysis requirements in development of the modal, corridor, and MPO plans leading to the STIP. In each case, HERS-OR was used to analyze the impact of different investment levels on the system and its users. HERSOR continues to be used to conduct various needs analyses and selected features of the model have been applied in producing special studies. The model has been integrated into the department's day-to-day activities, as the following examples of HERS-OR applications show.

Transportation Planning

In 1999, HERS-OR was used to analyze three scenarios for the Oregon Highway Plan update. Each of the scenarios included a different mixture of preservation and modernization improvements, ranging from "Preservation Only" to "High Cost Modernization." Modernization improvements are primarily focused on addressing congestion issues. The scenarios were analyzed to determine highway system condition and performance and user cost impacts over a 20-year analysis period (see figure below). Performance was reported in terms of average effective speed and user cost saving per mile.

Oregon's Highway Economic Requirements System: Scenario Analysis

  • At the start of the analysis, evaluate the current condition and performance of the highway system.
  • Using traffic growth projections for each highway section in the database, forecast future conditions and performance for each 5-year period (of a 20-year overall analysis period).
  • Identify section deficiencies based on analyst-defined triggers.
  • Analyze deficient sections to identify potential improvements.
  • For each section, list the possible improvements and apply economic criteria to rank-order the possible improvements according to relative economic merit.
  • Select improvements for systemwide implementation until the system funding constraints or user cost objectives are satisfied.
  • Consider analyst-determined substitutions for the improvements that the model selected for implementation.
  • Evaluate model-generated improvement costs and consider appropriate revisions.
  • Evaluate performance at the end of each funding period.

Through its HERS-OR analysis, ODOT was able to calculate the benefits accruing from each additional increment of preservation investment and each additional increment of investment in modernization. Based on the HERS-OR analysis, a case was successfully made that additional funds, over and above ODOT's current resources, could be invested in the system. The HERS-OR analysis also helped frame the difficult choices that arise from decreases and increases in spending when resources are constrained.

Special Analyses

Value of Travel Time. In the late 1990s ODOT was publicly criticized for producing inconsistent estimates of the value of travel time. While the estimates had been created for different purposes, clearly there was a need for uniform, fully documented, and readily accessible value of travel time estimates. To accomplish this, the portion of HERS-OR responsible for calculating travel time costs was extracted and used to provide a framework for developing official ODOT estimates of the value of travel time.

In the early 2000s, a major accident on I-5 closed a portion of the interstate for 13 hours and spotlighted a remaining problem associated with ODOT's travel time estimates: effectively disseminating the information internally. A local newspaper article about the accident cited an ODOT estimate of user costs associated with the incident that did not match the official ODOT estimates produced using the HERS-OR framework. In response to this problem, ODOT created two reference documents for agency staff and the media: "Unexpected Delay Map" and "Table of Estimates of the Cost of Unexpected Delay." Oregon analysts developed a spreadsheet to calculate the cost of delay based on the HERSOR methodology. This information was provided as reference points on a State map and is now available for quick and easy look-up. These information sources are routinely used by regional personnel in communicating with the public.

By using the value of travel time methodology from the HERS-OR model, the Oregon DOT has been able to report, with the credibility that comes from consistency, the travel time costs accruing from incidents that cause unanticipated delay, such as mud slides, rock falls, and major crashes. These results are provided to the public and help to not only generate interesting background information, but also demonstrate the importance of highway infrastructure to the citizens of Oregon. The estimates also serve as the basis for other time-related estimates of delay associated with detours, weight restrictions, construction work zones, and road closures.

Congestion Management System. Oregon's statewide Congestion Management System (CMS) provides information on transportation system performance. This information is intended to help decision makers identify, select, and implement policies and technologies that will alleviate traffic congestion. The CMS reports congestion trends on the State highway system and highlights congestion severity. The Oregon CMS uses the capacity analysis from HERS-OR-ODOT literally imported the HERS capacity module into its CMS.

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Updated: 06/27/2017
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