Roadway Network Database

The TPO monitors traffic congestion on over 425 roadway segments (950 directional links).  The Roadway Network Database contains current traffic data for all arterial and collector roads – the major roads in Polk County. 
The Roadway Network Database includes information on the current traffic volume and level-of-service for these major roads.  The report identifies both daily and peak hour traffic volumes.  Daily traffic volumes are reported in Annual Average Daily Traffic (AADT) – the typical traffic volume on a weekday over a 24-hour period.  Peak hour traffic represents the highest hourly traffic volume for period between 4 – 7 p.m.  It is reported as both a two-way volume and as directional volumes (east and west or north and south).

The peak hour traffic volumes are used to estimate the level-of-service for each roadway, in each direction.  Level-of-service refers to the quality of traffic flow.  It is the primary measure of traffic congestion.  Level-of-service (LOS) is measured on a scale of ‘A’ to ‘F’ with LOS ‘A’ being the best (free-flow traffic) and LOS ‘F’ being the worst (severe traffic congestion – think parking lot).

Download a copy of the current Roadway Network Database in GIS: 2017 Roadway Network Database GIS