Backtest memo · TR-2026-BT01SAMPLE DATA

Backtest — Contract I-21-4512, awarded 2021

Generated Aug 14, 2026 · 4:00 AM Trigger Backtest Source Illinois Tollway public records, 2015–2026
Predicted +6.0% from history available on the award date. The agency has since authorized +8.9%.
Meridian Heavy Civil Bid № 1Adjusted № 1
Award
$20.0M
Historical growth
+6.0%
median +6.1%
Predicted cost
$21.2M
Record
7 contracts
$172M awarded → $182M authorized

Recurring cause of growth: unforeseen underground conditions — 6 of 12 contracts.

I-19-4390 · Res. 21106 · +$2,215,000Source
"utility relocation conflicts requiring redesign of storm sewer alignment"
I-24-4855 · Res. 24102 · +$1,560,000Source
"differing site conditions in the west abutment excavation"

Limitations. Growth is computed from the agency's own published award and authorized amounts. Stated reasons are quoted verbatim from board resolutions, which are written to obtain approval and reflect the agency's own framing. Increases absorbed within contingency or below board approval thresholds never appear in public documents and are not counted here. This memo supplies a missing variable; it is not a recommendation.

A human decides from here