Monthly Variation Reports
formerly Annual Comparisons by Functional Classification
The figures contained in this report compare the average daily traffic volumes for each month by functional class of highway. The percent change is the change in traffic volume for each month over the time period.
Percent change = Vol (current year) — Vol (previous year) X 100
Vol (previous year)
Where Vol = average daily traffic volume for the month
The total system average column shows a simple average across all functional classes
The annual percentage change shown at the bottom of a report is a simple average of the 12-month period