In transportation engineering, the K factor is defined as the proportion of annual average daily traffic occurring in an hour.
K factors must be calculated at a continuous count station, usually an "automatic traffic recorder", for a year before being determined.
[2] Such forecasting includes the selection of pavement and inclusion of different geometric aspects of highway design, as well as the effects of lane closures and necessity of traffic lights.
The use of the K30 standard is mandated for the Highway Performance Monitoring System's comparisons of congestion.
The K Factor also helps calculate the peak-to-daily ratio of traffic.