FAQs - Distance Signs on interstate and freeway highways

• What cities are shown on the Distance Sign?

  Distance Signs may contain up to three lines of legend.
  
  The top line of the distance sign will show the closest community that is shown on the Advance Destination Sign for the next interchange. If the two communities shown on the Advance Destination Sign are the same distance away, the community with the largest population will be shown.
  
  The second line, if used, may show another community accessible at the next or subsequent interchange with preference given to the community closest to the exit.
  
  The bottom line shall display the name of the control city for the route.

• What is a control city?

  A control city is a major city on or near the interstate or freeway system, is a significant generator of traffic or a focal point for travel, and is used as a destination to provide long-range navigational information. The American Association of Highway and Transportation Officials (AASHTO) is responsible for approving and publishing the list of control cities for the interstate system.

• Where are Distance Signs installed?

  Distance Signs are included in the series of signs (route shield, speed limit, and distance signs) that follow an entrance ramp. If there is adequate space available the distance signs are installed after the entrance ramp.

• How is the mileage measured?

  The mileage shown on distance signs is the distance to a point near the center of the community. A public building such as a post office, city hall or courthouse is used as a point of reference for the center of the community. The mileage is rounded to the nearest mile.

• How do I request a Distance Sign?

  Please send a written request to the appropriate Iowa DOT District Office. Include in your request a description of the sign message you are requesting and the location where you would like the sign installed.