Historical Road Conditions
The Iowa Environmental Mesonet archives the road condition reports as generated by the Iowa State Patrol. From this page, you can generate a listing of road conditions per road segment for a particular month or a listing of all road conditions for a particular time. Currently, our archive is basically complete back to 14 Feb 2006.
You can find an archive of the raw text reports by navigating the IEM's
look for the .STOIA files. All timestamps are in Greenwhich Mean Time (GMT or UTC), which is 6 hours ahead of us in the winter. The directory structure of the site is ordered by year, month, and then day. The example URL is for 30 Jan 2005.
and an archive of the GIS shapefiles per report here:
look for the iaroads_* files. Again, timestamps are in GMT.