Rx for SMV Highway Safety: Be Conspicuous

Safely traveling roadways with agricultural equipment requires an extra degree of caution from the equipment operator and from general vehicle drivers sharing the road.
Rx for SMV Highway Safety: Be Conspicuous - Articles



Most agricultural producers need to move production equipment on public roads for tillage, planting, harvesting, and marketing crops. Livestock may also be moved on public roads by farm equipment. Safely traveling on roadways with agricultural equipment requires an extra degree of caution from the equipment operator and from general vehicle drivers sharing the road. Tractors and agricultural implements typically travel on roadways at speeds of less than 25 mph (40 km/hour). Motor vehicles travel at much faster speeds and drivers often do not understand the braking time needed to avoid a rear-end collision. Incidents involving motor vehicles and farm equipment can be deadly and costly. Greater visibility plays an important role in roadway safety by providing increased sight distance for decision making and stopping. Standards for lighting and marking, which include the SMV, have been developed by the American Society of Agricultural and Biological Engineers (ASABE) for tractors and towed equipment. Domestic manufacturers produce lighting reflectors for tractors and machinery based on these standards.

Slow Moving Vehicle Emblem

The SMV emblem is a highly reflective sign required on the back of all tractors, towed implements, and self-propelled implements used on public roads. The SMV is an equilateral triangle with a minimum height of 14 inches and constructed of reflective materials. The inner part of the triangle is a fluorescent orange material that provides visibility during daytime hours. The orange triangle is outlined by a red retroreflective material that enhances nighttime visibility. The emblem should be seen from a distance of at least 1,000 feet day or night. Emblems that have a metal or plastic backing, as well as decal emblems, are suitable for use. The ASABE standard specifies the quality and durability of the yellow-orange fluorescent triangle that provides daylight identification of slow-moving vehicles. The role of the SMV is to increase the visibility of your farm equipment on public highways through the use of conspicuity material.

Conspicuity material does what it says: it makes the equipment stand out, or be more conspicuous. The reason you want your equipment to stand out when on roads is to give motorists time to notice you and to slow down. Fluorescent material aids daytime visibility and reflective material aids nighttime visibility, but the materials don't last forever. The orange fluorescent center portion of the SMV emblem will fade and turn color over time, changing from orange to yellow, pink or white. This portion is the most vulnerable to light and moisture degradation because fluorescent dyes decompose. Maintaining fresh emblems with maximum fluorescence makes a big difference, especially in early morning or late evening hours. Retroreflective material as found in the outer border of the SMV emblem is intended to reflect the headlights of vehicles approaching from the rear at night. Retroreflective material holds up longer than fluorescent material. The retroreflective border material used in the manufacturing of new SMV emblems is different than older SMVs and can now be detected as far as a mile away compared to only a few hundred feet for the older SMVs.

SMV and Pennsylvania Vehicle Code

The use of the SMV emblem is mandated in Pennsylvania by state law and outlined in the following Pennsylvania Vehicle Code:

#4529. Slow-Moving Vehicle Emblem

  1. General rule--All implements of husbandry, commercial implements of husbandry and special mobile equipment designed to operate at 25 miles per hour or less and all animal-drawn vehicles shall, when traveling on a highway, display on the rear of the vehicle a reflective slow moving vehicle emblem as specified in regulations of the Department. The use of the slow moving vehicle emblem shall be in addition to any other lighting devices or equipment required by this title.
  2. Limitations on use or display--No person shall use or display the slow moving vehicle emblem except as provided in this section nor shall any person display the emblem on a vehicle traveling at a speed in excess of 25 miles per hour.
  3. Towed vehicles--The emblem shall be required to be displayed on a slow moving vehicle which is being towed on a highway unless the towing vehicle displays the emblem in such a manner as to be clearly visible from the rear.

The term "highway" as used in the Code, is officially defined as "the entire width between the boundary lines of every way publicly maintained when any part thereof is open to public use for purposes of vehicular traffic."

Placement and Maintenance of an SMV

The correct placement of the SMV is vital for it to be effective. Use the following guideline when attaching an SMV emblem:

  • With the triangle pointing upward, place the SMV emblem at the rear center or left rear of center of the vehicle or implement.
  • Center the SMV emblem horizontally on the vehicle.
  • The bottom edge of the triangle should be between 2 - 10 feet above the ground.

The purpose of an SMV emblem is to increase visibility of agricultural equipment (implements of husbandry). It is important that the SMV emblem is not used for any other purpose which can decrease its effectiveness as a means of identifying slow moving agricultural equipment. For example, the SMV emblem should not be used to mark a driveway or mailbox.

Agricultural producers are responsible for maintaining SMV emblems and replacing them when necessary. SMV emblems can become covered with dirt or fade over time due to continual sun exposure. To maintain the necessary reflective properties of the SMV, regularly clean the emblem and replace it when it begins to fade.

Speed Indicator Symbol

Tractors and agricultural equipment are classified as slow moving vehicles. However, some newer tractors are capable of traveling over 25 mph. States continue to discuss the use of the SMV symbol on these high speed tractors. In response, ASABE revised the S276 "Slow Moving Vehicle Identification Emblem (SMV) Emblem)" and S279.16 "Lighting and Marking of Agricultural Equipment on Highways" to standardize the use of a speed indicator symbol (SIS) on the rear of higher speed tractors that indicates their maximum speed.

Reflective Tape and Lighting

New federal surface transportation regulations were signed into law in 2012. This legislation included the Agriculture Machinery Illumination Safety Act (AMISA). This new legislation is to be implemented by the U.S. Department of Transportation within two years of its signing. The AMISA is based upon ASABE Standard 297.14 (or successor standards) and is not retroactive to any existing equipment. The latest version of ASABE's Lighting and Marking of Agricultural Equipment on Highways standard is ASABE 279.16. Table One summarizes its recommendations.

Table 1 - Surface Transportation Legislation for Lighting & Marking of Ag Equipment
ItemASAE Recommendation - NumberASAE Recommendation - ColorASAE Recommendation - MountingPA Requirements
Headlights2WhiteOn either side of vehicle centerline at same heightSame as ASAE recommendation1
Taillights2RedSymmetrically mounted to rear between 1.3' & 10' high and no greater than 5' to left & right of machine centerOne mounted at each side on rear1
Hazard FlashersMin of 2Amber1.3' to 12' high & symmetrically spaced as widely apart as practicable to be visible from front & rear (60 to 85 flashes/min)Two if double-faced with amber to front & red to rear. Four if single faced - amber on front corners & red on rear1
Turn Indicators2Amber or Red1.3' to 12' high & symmetrically spaced as widely apart as practicable to be visible from front and rearNot required
SMV Emblem1Fluorescent red-orange triangle for daylight with red retroreflective border for nighttimeOn rear center or rear left for maximum visibility of 1,000 feet day or night, 2' to 10' above groundAll implements of husbandry designed to operate at 25 mph or less shall display the SMV on rear of vehicle at all times on highways.


Red on rear of machine.

Yellow on front of machine

May be either part of tail lamp lens or conspicuity material. Size to be 2" wide by 4.5" long for machines < 6.7' wide. Size to increase to 2" by 9" for wider machines which is >6.7' wide.One red reflex reflector or reflective tape at rear on each side & one amber reflex reflector or reflective tape at front on each side with size of reflector to be 3 square inches or more1
Rotating Beaconsnot RequiredOne flashing or revolving yellow light or strobe light.
Conspicuity material to better define size and to increase visibility (machinery or towed equipment)Red retroreflective & red-orange fluorescent

Yellow retroreflective

Visible to rear: Red-orange nonreflective fluorescent material on rear corners within 25" of left and right outer corners of the machine. Distance between materials should not exceed 6'.

Visible to front:Yellow retroreflective material.2 Reflective material to be within 16" of outside corners.
SMV only

1 between sunset and sunrise and during reduced visibility

2 for trailing equipment > 16.4' behind hitch point, display amber/yellow reflectors spaced < 16.4' apart on sides.

Note: Additional lighting and implement accessories typically require a 7-terminal receptacle.


  • American Society of Agricultural and Biological Engineers, 2010, ANSI/ASAE 276.7 W/Corr. 1. Slow Moving Vehicle Identification Emblem (SMV Emblem). St. Joseph, MI. Retrieved from elibrary at ASABE
  • American Society of Agricultural and Biological Engineers, 2013, ANSI/ASAE 279.17. Lighting and Marking of Agricultural Equipment on Highways. St. Joseph, MI. Retrieved from elibrary at ASABE
  • Agricultural Equipment on Public Roads (2009) North Central Education/Extension Research Activity Committee 197. Cooperative State Research, Education, and Extension Service. United State Department of Agriculture. Retrieved at CSREES.
  • U.S. Congress. House of Representatives. Surface Transportation of 2012. H.R. 112th Congress, 2nd Session, 2012. Retrieved September 14, 2012 from House Bill HR4348(pdf).