CDOT Performance Data Business Plan - Cambridge Systematics

CDOT Performance Data Business Plan
Unit of Measure: Grade
Calculation:
1. Calculate the deck area of each structure as follows:
2. Determine which bridges are “good or fair” using the criteria described
above.
3. Calculate percent good or fair as follows:
∑
∑
100
4. Convert result to a letter grade using the thresholds defined above.
Update Frequency: Annual (Data are collected biannually for each bridge.
However, the inspections are performed on a rolling basis, so it is recommended
that the measure be reported annually.)
Additional Notes: The criteria for defining good/fair/poor are based on
national standards used to determine eligibility for Federal bridge funds.
Bridges in poor condition are eligible for Federal reconstruction funds. Bridges
in fair condition are eligible for Federal rehabilitation funds. Bridges in good
condition are not eligible for Federal funds.
Sufficiency rating is reported on a scale of one to one hundred. It is based on
condition data and bridge characteristics related to serviceability and essentiality
for public use. Structurally deficient (SD) status indicates that a bridge has a
significant condition defect. Functionally obsolete (FO) status indicates a design
issue, such as insufficient shoulder width. All three metrics are based on data
collected biannually.
3. Pavement Condition
Existing Measure: The percent of miles of pavement that are classified as
“good” or “fair” based on remaining service life (RSL) is currently tracked and
reported by CDOT. RSL thresholds are as follows:
Poor – RSL < 6
Fair – 6 ≤ RSL ≤ 10
Good – RSL ≥ 11
Recommendation: Recommended modification to this measure is to combine
RSL with percent of miles of pavement classified as “good” or “fair” based on IRI
(International Roughness Index), and then convert the result to a letter grade.
The recommended IRI thresholds are as follows:
Poor – IRI > 170
Fair – 95 ≤ IRI ≤ 170
Good – IRI < 95
3-10 Cambridge Systematics, Inc.