Iowa Unique State Laws

Under Iowa law, what vehicles are required to display a slow-moving vehicle (SMV) triangle?

By DMV Master Editorial Team Updated Verified against Iowa Code §321.383
A

Only farm tractors.

The rule covers more than tractors.

B

Any vehicle operating on public roads at 35 mph or less.

Correct answer

C

Vehicles without working taillights.

Taillights are a separate requirement.

D

Only Amish horse-drawn buggies.

The rule is not limited to buggies.

Detailed Explanation

Iowa requires the orange reflective Slow-Moving Vehicle (SMV) triangle to be displayed on the rear of any vehicle using public roads and traveling 35 mph or less. This includes tractors, horse-drawn vehicles, construction equipment, and certain utility carts — common in rural Iowa.

Source: Iowa Code §321.383

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