Over the past five years, guide signs at Iowa’s interstate interchanges have been revamped with an eye for modern-day driving needs. The last major stretches of interstate will be switching over this summer, and the style will spread to other four-lane roads as replacement cycles warrant.
Since the beginnings of the interstate highway system in Iowa, there had been a standard pattern at cross roads. Each interchange had independent shields arranged on poles/brackets, with mileages given to two “control cities” (major cities on the freeway) and often a third location on the intersecting route. If the intersecting route was a state or US highway, a shield indicating such would be included in at least one assembly. Examples are shown below:


This style was in marked contrast to Minnesota, Illinois, and Missouri, all of which used at least one large, single-panel BGS-type sign for interchanges, and none of which included distances.
Starting in 2009, the Iowa Department of Transportation began moving away from this form. The 2009 Manual for Uniform Traffic Control Devices, or MUTCD, omits inclusion of mileage at interstate crossroads. The specifications overall use larger (Clearview) letters, and there is obviously a greater visibility of a single-panel green sign than individual shields. For more details, click on the jump.
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