About the DOT

Roads, Streets, and Bridges

  • There are more public road miles in Iowa than interstate miles in the entire 50 states.
  • Iowa ranks 14th in the nation in number of miles of roadway. (2018)
  • There are approximately 36 miles of road for every 1,000 people in Iowa.
  • There are 1,481 bridge structures in Iowa that are made primarily of wood and currently open to traffic.

2019 Public Road Length - Miles by Ownership
Ownership Miles
Iowa DOT 8,902*
Counties 89,698
Municipalities 15,442
Parks and institutions 602
Federal agencies 138
Total miles 114,782*

*Totals exclude ramps. The Iowa DOT maintains 9,617 miles of roadway, including 715 miles of ramps.


2020 BRIDGES - NUMBER OF BRIDGES
Ownership Bridges
Iowa DOT 4,144
Counties 18,576
Municipalities 1,190
State parks 29
Local parks 4
Other state agencies 3
Private 15
Railroad 357
Corp of Engineers 3
Bureau of Indian Affairs 1
Bureau of Fish and Wildlife 1
National Park Service 2
Corps of Engineers 6
Total 24,325


Bridge Rating Definitions

  • Good - Deck, Superstructure, and Substructure or Culvert condition ratings are 7, 8, or 9.
  • Fair - One or more condition ratings for the Deck, Superstructure, Substructure, or Culvert are 5 or 6.
  • Poor - One or more condition ratings for the Deck, Superstructure, Substructure, or Culvert are 4 or less.

Primary Highway System - Age of Bridges by Decade


Primary Highway System - Condition of Bridges