Failing Grade: When the study has a failing grade, below C, for the entire U.S. One, the County Commission has consistently rejected the study (2019, 2023) because most development, other than single family homes, would be curtailed or traffic impacts mitigated in most areas of the Keys.    

Passing Grade: When there is a passing grade of C or above the Commission approves the study. The 2025 study had a passing grade and was approved.

There was significant public comment critical of the annual report. The Average Daily Trips documented for 2025 were the lowest number of daily trips recorded for the last 15 years.  Few found the statistics believable.  

The studies must be done during the peak season - before the end of March.  The 2025 study was delayed and completed later than “peak season” as required.

Islamorada Traffic according to the Study: There were three traffic segments out of 24 segments in the Keys that had a failing grade in 2025, all the failing grades were in Islamorada: Lower Matecumbe, Upper Matecumbe, Windley Key.  Plantation Key had a passing score because construction delays (FKAA Water Pipeline project) are ignored.  But it didn’t mean the congestion didn’t impact drivers!

Islamorada Standards: In Marathon and unincorporated Monroe County, if a segment falls below a Grade C, construction in the segment can only be approved with costly mitigation, except for single family homes. In Islamorada, the determining traffic is measured on an overall countywide basis not dependent on individual US 1 segments. Therefore building permits can continue to be issued in spite of three segments in Islamorada falling below a Grade C.