Division of Planning
Office of Technical Services
Axle Correction Factors
Axle correction factors are calculated by analyzing data from Automatic Traffic Recorders (ATR’s) and short term portable vehicle classification counts. An average axle correction factor is calculated for each functional class.
Axle correction factor = Total number of axles / Total number of vehicles
This calculation results in the average number of axles per vehicle. The factors listed in the table are the reciprocals of the values.
To adjust the axle impulses received during a volume count to the approximate number of vehicles use the following equation.
Number of Vehicles = Total number of Axle Impulses x Axle Correction Factor
The factors should be used with judgment when atypical traffic patterns are encountered, such as traffic volumes near major recreational areas (e.g. King’s Island, shopping centers, football and baseball stadiums, etc.)