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 1) Adjusting a count or estimate of the hourly volume of vehicles to account for the effects of prevailing traffic conditions. This module addresses step one. 2) Adjusting the free-flow speed for the prevailing design conditions of that section. The module "Free-Flow Speed Adjustment" addresses step two. The hourly volume (in vehicles per hour) is changed to an equivalent passenger-car flow rate by allowing for the effects of heavy vehicles (buses, trucks and recreational vehicles) on traffic flow, the variation of traffic flow during the hour, and the characteristics of the driver population. The passenger-car equivalent flow rate is then reported on a per lane basis. Passenger-car equivalents in passenger car per hour per lane (pcphpl) are determined using the following equation: 
Where vp = 15-minute passenger-car equivalent flow rate (pcphpl) Values for the driver population factor, fp, range from 0.85 to 1.0. In general, the value of 1.0 is used to reflect commuter traffic. Use of a lower value reflects more recreational traffic. The peak hour and heavy-vehicle adjustment factors are described in their respective modules. The demonstration for this module uses values derived from the peak-hour and heavy-vehicle adjustment factor modules.
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