The Iowa Department of Transportation's Systems Planning Bureau, in cooperation with the Federal Highway Administration, prepares this annual traffic report. This report is used by federal, state, and local governmental agencies in determining: 

  • highway needs
  • construction priorities
  • route location
  • environmental impact studies; and
  • the application of appropriate design standards. 

The public uses this information in determining the amount of traffic that passes a given area as they make their development plans and propose land use changes. The above reflects only a few of the many technical uses for this data.

Starting in the 2010 report, traffic-volume segments include the mainline, ramps, loops, and connections at interchanges while inner legs or at-grade level intersections are not shown in the annual report.  

Prior to 2010, ramps (all types of arrangements and sizes of turning roadways connecting two or more "legs") at interchanges or at-grade intersections are not shown in these reports. Traffic volumes for these road segments may be obtained from the Systems Planning Bureau by contacting:

Traffic Books
Annual Traffic BookHistorical Traffic Book
20242000
20221998
20201996
20181994
20161992
20151990
20141988
20131986
20121984
20111982
20101980
20091978
20081976
20071974
20061972
20041970
20031968
20021965
 1962
 1959
 1956
 1953
 1951
 1949
 1941
 1938
 1934