by on

The 2012 Traffic Flow Data Map is now online and the 2013 map is in the works. The map is a great general reference tool. It can be used as a quick reference for the traffic volume on a specific arterial and to compare traffic volumes between two arterials. It gives users a good idea of the distribution of traffic across the city. As you zoom in on the map you’ll see numeric labels placed on the arterials. The numeric labels are placed as close as possible to the actual count location used for each flow segment. As you get further from the count location on the arterial, the value shown on the map is less likely to represent the actual volume on the street.

At each location a one week count is collected. These in turn are collected throughout the year. This count is then adjusted based on the month of the year in which they were collected to make it possible to compare counts collected in different months. These adjustment or expansion factors cannot be computed until after the end of the year since they require data from all months of the year to be compared. The data used to generate the adjustment factors comes from monthly counts at selected locations. The data on the map represents the Average Annual Weekday Traffic. This is the data averaged to show the 24 hour weekday volume. Weekend volumes are generally lower.

Comparisons to past maps is possible since the collection locations and methods remain consistent, but keep in mind that major construction projects may have influenced traffic volumes on a specific segment in certain years. These can lead to inconsistent changes in traffic volumes.