StreetSaver Blog

For Performance Management, is IRI a Better Indicator?

by Sui Tan | Aug 28, 2015
The recent MAP-21, FHWA’s Notice of Proposed Rule Makings (NPRM) have heightened the importance of IRI as one of the performance metrics on pavement conditions that is required in the state DOT’s asset management plan. Why would FHWA pick IRI? For one important reason – this is by far the only national-level data that the state DOTs collect and submit every year for Highway Performance Monitoring System (HPMS) reporting. Many state DOTs have IRI data since 1990 when it was first required by FHWA. So it is reasonable to see why the IRI became one of the performance metrics proposed, and state DOTs will be required to set a target in their asset management plan.

Asset Management Plan

FHWA’s NPRM on asset management plan requires state DOTs to establish an asset management plan “to improve or preserve the condition of the assets and the performance” of pavement and bridge assets. This plan shall include, at a minimum, objectives and measures, performance gap identification, life-cycle cost and risk management analysis, and a financial plan with investment strategies. [23 U.S.C. 119(e)(4)].

How exactly will IRI be used in the state’s asset management plan? What is the target to set? FHWA has proposed a minimum of no more than five percent of poor condition, and further identified poor is IRI of 170 inches/mile in area with population fewer than one million and 220 inches/mile in area with population greater than one million. Many state DOTs, including AASHTO, have commented that managing by minimum condition will lead to “worst first” approach.  AASHTO further indicates that ”to use such limited data mined from the HPMS database to establish correlations between system performance and investment decisions is not recommended.”

So I am going to be bold and assume that every state DOT is facing inadequate funding to sustain its pavement asset investment, and hence has accumulated deferred maintenance. To achieve the “state of good repair”, there has to be a way to effectively measure the effort on reducing the deferred maintenance costs. Fortunately, FHWA has already defined the minimum components to be included in an asset management plan as stated earlier. To put it in more of a layman’s terms, the plan will include asset inventory, condition assessment, maintenance and rehabilitation strategies, and proposed plans to achieve the state of good repair. While these components do not directly address contributors to the accumulation of deferred maintenance, if implemented effectively, they could provide a “strategic and systematic” approach to assist DOTs in prioritizing maintenance efforts and benchmarking performance, and provide Congress the data needed to work out long-term funding solutions.

My point is, from an asset management approach, IRI so far has not directly correlated to the reduction of deferred maintenance. My next blog will continue to explore other factors when considering if IRI is a better indicator as a MAP-21 performance metric.

Part II: For Performance Management, is IRI a Better Indicator?

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