Federal regulation requires that Metropolitan Planning Organizations (MPOs) support State DOT pavement and bridge condition performance targets or establish their own targets every 2 and 4 years, respectively. Since these targets were first established in 2018, SEMCOG, in cooperation with MDOT, updated the targets as required. Targets must be established on the National Highway (NHS) System throughout the state. The NHS includes 7,381 lane miles of road in the SEMCOG region. MDOT owns 62.4% of those lane miles. MDOT also has jurisdiction of 91.8% of the bridges that are reported on through the target-setting process in the region.
How is Pavement Condition Measured?
Specific Pavement targets are set for:
- Percentage of pavements on the Interstate System in Good condition
- Percentage of pavements on the Interstate System in Poor condition
- Percentage of the non-interstate National Highway System in Good condition
- Percentage of the non-interstate National Highway System in Poor condition
The federal pavement performance measure uses a combination of the International Roughness Index (IRI), percent cracking, percent rutting, and percent faulting to indicate pavement condition.
The IRI is an automated road profiling system that measures the variation of a road’s surface. While SEMCOG and Michigan use the Pavement Surface Evaluation and Rating (PASER) road condition rating system as a tool to indicate a road’s structural integrity, other states use many other rating systems to track pavement conditions. IRI allows condition ratings to be both automated and comparable across states.
This performance measure applies to both the federal interstate system and the rest of the National Highway System (NHS), which includes principal arterials and other roads that are important to the nation’s economy, defense, and mobility.
SEMCOG’s regional pavement condition performance measure is based on a different data source and is applied to a broader network of roads, so it is not comparable with this federal performance measure.
How is Bridge Condition Measured?
Bridge condition ratings are based on three bridge elements: the deck, the superstructure that supports the deck, and the substructure. The overall bridge condition rating is based on the worst rating across the three elements. Bridges are inspected on a regular basis with bridges rated good or fair inspected every other year and bridges rated poor inspected every year. The bridge condition ratings are stored in the National Bridge Inventory (NBI).
This federal performance measure uses the NBI ratings for all bridges carrying the National Highway System (NHS), which includes the Interstates, principal arterials, and other roads that are important to the nation’s economy, defense, and mobility. Non-NHS bridges are not included in this measure. This performance measure is also weighted by the overall deck area of individual bridges so that bridges with large decks will affect the performance measure more than bridges with smaller decks. SEMCOG’s regional pavement condition performance measure is also based on data from the NBI, but since this federal performance measure is limited to the NHS and weighted by deck area, the regional and federal performance measures are not comparable.
On April 28th, 2023 SEMCOGs Executive Committee approved the performance targets for pavement condition.
| Measure | Baseline Performance 2022 | 2-Year Target 2023 | 4-Year Target 2025 |
|---|---|---|---|
| Percent Interstate in Good Condition | 70.4% | 59.2% | 56.7% |
| Percent Interstate in Poor Condition | 1.8% | 5.0% | 5.0% |
| Percent Non-Interstate NHS in Good Condition | 41.6% | 33.1% | 33.1% |
| Percent Non-Interstate NHS in Poor Condition | 8.9% | 10.0% | 10.0% |
Bridge Condition
On April 28th, 2023 SEMCOGs Executive Committee approved the performance targets for bridge condition.
| Measure | Baseline Performance 2022 | 2-Year Target 2023 | 4-Year Target 2025 |
|---|---|---|---|
| Percent NHS Deck Area in Good Condition | 21.8% | 15.2% | 12.8% |
| Percent NHS Deck Area in Poor Condition | 7.0% | 6.8% | 5.8% |