Iowa Primary Highway System - Signage

Signage

See also: Manual on Uniform Traffic Control Devices

Standard highway markers used in Iowa

Shield type	1 digit	2 digits	3 digits
Interstate	none
U.S. highway
State highway
County highway	none

U.S. and Iowa highways are marked with a 24-by-24-inch (61 cm × 61 cm), or rarely, a 36-by-36-inch (91 cm × 91 cm) black sign with a white shield or white circle, respectively. To make room for additional digits, fonts are adjusted accordingly: One-digit routes use MUTCD Series D, two-digit routes use MUTCD Series C, and three-digit routes use MUTCD Series B. Additional room for numbers on three-digit routes can be created by using 10-inch (25 cm) numbers.

Interstate Highways in Iowa are signed with, compared to current MUTCD standards, an older style blue and red shield which features smaller numbers, wider striping, and the state's name on every shield. When in use in the field, two-digit shields are 36 by 36 inches (91 cm × 91 cm), while three-digit shields are 36-by-42-inch (91 cm × 110 cm), and 24 by 24 inches (61 cm × 61 cm) and 25 by 30 inches (63 cm × 76 cm), respectively, on intersecting roads.

All county routes are signed with the MUTCD-standard blue pentagonal shield, however some older signs still remain.