The SMV Emblem means “Slow Moving Vehicle”

Dear Farmers:

What does that red and orange triangle with the cut-off corners mean to you? I would hope that you recognize it as a Slow Moving Vehicle (SMV) Emblem and that the vehicle to which it’s attached is moving at less than 25 miles per hour.

What does that red and orange triangle with the cut-off corners mean to a non-farmer: someone from town, the city, even a “rural resident”? When they see it, do they know to “slow down” because the vehicle bearing it is moving slowly? Or, have they been conditioned to ignore it because too many times they’ve seen it going down the road at 45, 50, 55 miles per hour (attached to a wagon or piece of equipment being pulled by a pick-up truck, or on the back of an implement being hauled on a semi …)?

You know, what we practice is how we automatically respond: It’s called habit. So, if drivers get in the “habit” of not slowing down when they see an SMV Emblem because “the Emblem is always traveling close to my speed,” when they do happen to come up behind that tractor/wagon being driven by your wife/husband/kid that is going only 15-20 mph, how will they react??? It could be an accident waiting to happen!!

The SMV Emblem was developed by the Department of Agricultural Engineering at Ohio State University in 1962 in response to studies that showed about 65 percent of roadway accidents involving slow moving vehicles were rear-end collisions. Something was needed to warn those coming from behind that the tractor/wagon/equipment in front of them was going less than 25 miles per hour! After much testing of various designs, it was found that a triangular-shaped emblem with a 12-inch-high florescent orange center and three 1 ¾-inch-wide reflective borders was most effective for day and night visual identification. The “cut off corners” happened after field testing.

So, how do we protect this icon so it can continue to protect us? We use it properly!

• Clean, undamaged, still bright

• Visible 500 feet to the rear

• Triangle point facing upward

• Mounted 2-feet to 10-feet from the ground

• Located in the center or as near left-center of the implement as possible

• Securely/rigidly attached (No “blowin’ in the wind”!)

• MAXIMUM SPEED = 25 miles per hour

••• Even when that wagon/implement is being pulled by a pick-up truck!

••• Removed or covered when the vehicle is being transported on a truck or trailer.

Oh, yeah: There are now tractors designed to go over 25 mph. Do they need to have an SMV Emblem? Yes! They also need to have a Speed Identification Symbol (SIS) posted that shows the tractor’s maximum speed. This SIS needs to be visible 500-feet to the rear. Any wagon or implement towed behind these tractors also need to show the SMV Emblem and the SIS. This law went into effect in October of 2007. (The SIS needs to be ASABE approved and can be obtained through your implement dealer.)

As a farm manager, it is your responsibility to ensure that those working with you know, understand, and practice safe procedures. Using the SMV Emblem properly is one of the Most Important procedures to practice! Be sure your workforce knows and understands the rules.

Practicing proper use can help protect all of us from rear-end collisions. It’s the responsibility of all of us to condition drivers so that the SMV Emblem means “Slow Moving Vehicle.”


Debbie Brown

ANR Educator

OSU Extension, Shelby County

Sources used:; See also – Fact Sheet AEX-598-08 on Visibility of Ag Equipment:

Sources used:; See also – Fact Sheet AEX-598-08 on Visibility of Ag Equipment: