Determination of Lane Volumes:

Lane volumes are determined by applying adjustment factors to the input volumes, and dividing by the number of lanes. Most of the adjustments are a straightforward parallel to the HCM. The main exception is the shared lane left turn adjustment, which requires knowledge of the signal-timing plan in the HCM operational procedure. Since the signal-timing plan has not yet been established, an approximate model must be applied to estimate the portion of the shared lane that will be used up by the left turn traffic. After that point, the left turn traffic in the shared lane will be ignored.