6.1.1.4 Future Directions in Performance Measures

Future Directions in Performance Measures

As agencies advance the maturity of their practices and move towards investment decisions across assets and modes (as discussed in Chapter 5), there is increasing interest in the use of leading measures and asset performance measures that can be used in concert with asset condition measures.

Asset management plans document the processes and investment strategies developed by an agency to manage its infrastructure assets. These asset management plans support an agency’s performance-based planning and programming processes for making long-term investment decisions and feed shorter-term project and treatment selection activities. Together, these activities ensure the investment decisions of an agency are aligned with performance objectives and goals.

Examples of innovative new performance measures include:

• Financial Measures – Internationally, financial performance measures have been used successfully to express whether the level of investment has been adequate to offset the rate of asset deterioration or depreciation. For example, the Queensland Department of Infrastructure and Planning uses an Asset Sustainability Ratio defined as the capital expenditure being made on asset renewals (e.g., improvements) divided by the depreciation expense (discussed further in Chapter 4). If the ratio is less than 100 percent, the level of investment is not adequately replacing the depreciation occurring each year. Queensland also uses an Asset Consumption Ratio comparing the current value of the depreciable assets to their replacement value in order to show the aged condition of the assets.

  In the United States, some agencies are evaluating the use of an Asset Sustainability Index (ASI), which is the ratio of the budget allocated to address needed improvements identified by a pavement or bridge management system (FHWA. 2012. Asset Sustainability Index: A Proposed Measure for Long-Term Performance, Federal Highway Administration, Washington, D.C.). The ASI is a unitless measure that allows comparisons across asset classes and provides an overall assessment of the adequacy of an agency’s investment in its assets. Since it is unitless, an agency could individually calculate a Maintenance Sustainability Ratio, a Pavement Sustainability Ratio, and a Bridge Sustainability Ratio that are all combined into an overall ASI. One of the difficulties in calculating the ASI is defining the needed level of investment since needs are significantly impacted by targeted condition levels. Slight changes in targeted conditions can have a significant impact on the resulting ASI calculation.

• Life Cycle Measures - A life cycle performance measure is a relatively new leading measure, promoting the selection of sound, long-term strategies best able to maximize performance at the lowest possible cost. There are several life cycle performance measures under consideration, including the Remaining Service Interval (RSI), validated under an FHWA-sponsored research project. The RSI is based on identifying a structured sequence of the type and timing of various repair and replacement actions needed to achieve a desired LOS over a long timeframe at the minimum practicable cost. The results of the RSI evaluation may be used to generate a Life Cycle Impact Factor, summarizing the difference in life cycle costs associated with the various strategies being considered. Documentation from a pilot implementation of the RSI approach is available through the FHWA (https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/21006/21006.pdf).
• Sustainability Measures – With an increased focus on identifying long-term sustainable solutions to transportation system needs, agencies may seek to develop new sustainability performance measures in order to properly indicate the impact a proposed solution may have on environmental conditions. The use of a recycling measure for gauging the amount of recycled material used in road construction is an example of this type of measure, as are measures for monitoring carbon dioxide emissions.
• Equity Measures -The increased emphasis on equity, inclusion, and diversity is impacting planning and investment decisions at several transportation agencies. As equity considerations are added, there has been some discussion related to the types of measurable performance measures that can be used without bias toward certain users or modes of transportation. In a case study prepared by the FHWA’s Transportation Asset Management Expert Task Group, a suggestion was made to further explore both quantitative and qualitative performance measures in this area.