late in the afternoon during fall harvest and you are hauling
an empty wagon back from the elevator. Without warning a car
hits your wagon from behind.
early June and you are hurrying to finish planting after a
break in the weather. As you slow down to turn left into a
field, a car trying to pass sideswipes your tractor.
situations are common in Iowa. Between 1988 and 1992, the
Iowa Department of Transportation (IDOT) recorded 1,477 accidents
on public roads and right-of-way that involved farm vehicles,
almost 300 per year. Accidents occurred throughout the year,
but were somewhat more common during fall harvest. In 1992,
48 percent of all accidents involving farm vehicles occurred
from October through December in a delayed, drawn-out harvest.
most common accidents occur when the approaching motorist
hits a farm vehicle from behind (rear-end collision), or when
a passing motorist hits a farm vehicle that is attempting
to make a wide left turn (left sideswipe). These two situations
each accounted for 22 percent of the total number of two-vehicle
accidents in Iowa during 1988-1992 that involved a farm vehicle.
only a small percentage of vehicular accidents lead to a fatality,
the National Safety Council and IDOT data show that an accident
involving a farm vehicle is about five times more likely to
produce a fatality than other types of motor vehicle accidents.
publication discusses several reasons why these accidents
occur, and what makes accidents involving a farm vehicle more
likely to produce injuries and death than other types of accidents,
and how to reduce your risk.
a farm vehicle is involved in an accident in the public right-of-way,
there often is a large difference in the relative speed of the
two vehicles. A passenger car traveling at 55 miles per hour
approaches a tractor traveling in the same direction at 15 miles
per hour at a rate of 59 feet per second. If the car does not
slow down, it reduces the distance between itself and the tractor
by the length of a football field in just 5 seconds.
can quickly come up on a farm vehicle unless they brake as
soon as they see the farm vehicle. However, a car traveling
at 55 miles per hour requires 224 feet of total stopping distance
(for average reaction time and braking). Therefore, the driver
of the car in the previous example would have only a few seconds
to decide to slow down and avoid a collision with the tractor.
two vehicles collide in an accident, a rough measure of the
amount of energy that must be absorbed by metal, brakes, bodies,
etc., is the difference in the square of the two vehicles'
speeds (if both vehicles are going in the same direction).
If the two vehicles in the example collided with a 40 mph
difference in speed (55-15), there would be 2,800 units of
energy on impact (552 - 152). A collision of two vehicles
traveling at speeds of 45 mph and 55 mph has only about a
third as much energy on impact (552 - 452 = 1,000). When vehicles
are traveling in opposite directions, energy increases.
motorists may not immediately recognize farm equipment on roadways
or be aware of the special hazards they present. Lighting and
reflector locations on tractors, combines, and other farm equipment
are different from other motor vehicles. During either day or
night, an unfamiliar vehicle outline may delay recognition of
farm vehicles by the non-farm motorist. Loads on farm vehicles
may be wider than other vehicles, which present special hazards
for other motorists when left, right, rear, and front projections
are not easily recognizable.
slow-moving vehicle (SMV) emblem is recognizable to many non-farm
motorists. It's important to maintain SMV emblems, as well as
other reflectors, lighting, and equipment systems, to provide
maximum visibility of farm vehicles to other motorists. A check
of lighting and marking on 130 tractors and wagons during the
1992 harvest at Iowa grain elevators showed that although front
lighting (both white and amber flashing warning lights) was
being well maintained, rear lighting and marking was often substandard.
Because a common accident situation involves a second vehicle
approaching from the rear, equipment operators should pay special
attention to rear lighting and marking.
motorists may not understand farm equipment limitations, or
see hidden field entrances. For example, the broad turning radius
of many tractor-implement combinations requires operators to
steer slightly to the right before making a wide left turn.
Although a tractor operator may be using a left-turn signal
it may be hidden from the rear by another implement, or motorists
may ignore the signal and think the tractor is turning right.
The result is a left sideswipe of the farm vehicle by the non-farm
motorist who is trying to pass the farm vehicle.
sure you're visible. Maintain existing lighting and
marking on farm equipment. Clean reflectors, light lenses,
and mirrors of mud, snow, ice, manure, or other debris before
entering public right-of-way. Replace cracked lenses and
burned-out light bulbs. Repair wiring if necessary to make
lights operative. Replace faded SMV emblems. Maintain or
add rear view mirrors to allow vision around the side of
wagons or wide loads.
the law. Become familiar with requirements of the Iowa
Code and recommendations of the American Society of Agricultural
Engineers (ASAE) for lighting and marking farm equipment
(see other publications listed below). Consider installation
of additional lighting and reflectors if equipment does
not meet ASAE recommendations. Add marking and lighting
to the rear of implements used on roadways and implements
that obscure rear tractor lighting. If loads project more
than four feet from the center of your vehicle, add reflectors
or lighting to mark the extreme left and right projections.
defensively. All roadway travel is a team effort between
yourself and other drivers. Do not assume that other drivers
will see you pulling out of a driveway or anticipate your
turn into a field. Allow plenty of distance before pulling
in front of traffic. Assess alternate routes to the field
and/or different travel times during which you can avoid
high traffic. For example, can a morning chore schedule
be changed to avoid roadway travel during a peak commuter
much do you know?
many accidents on Iowa public roads involve farm vehicles
the two most common situations when two vehicles are involved
in a farm vehicle accident.
involving a farm vehicle are ______ to produce a fatality
than other types of traffic accidents.
times as likely
car traveling 55 mph is 100 yards behind a tractor traveling
at 15 mph. How long does it take for the car to catch up
with the tractor?
lighting and reflectors often are not well maintained?
answers at the end of the next section.
can you do?
the condition of lighting, reflectors, and SMV emblems on
farm equipment. Repair or replace as needed.
where additional reflectors, lights, and mirrors are needed
for wide loads and those that obscure rear tractor lighting.
with farm equipment dealers and suppliers about the availability
and cost of additional lighting and marking.
travel routes, if possible, to avoid times and locations
of peak roadway use.
driving, be aware that traffic behind you will be trying
to pass and may not anticipate your movements, such as a
wide left turn.
2-rear-end collision and left sideswipe by passing vehicle;
3-d; 4-a; 5-b.
covers only some aspects of farm equipment transportation on
public right-of-way. For more information, check out these publications:
Equipment Safety on Iowa Roads, available from the ISU
Extension farm safety specialist.
SMV emblems for your safety, Pm-1265j, from the Safe
Farm series, available at your local extension office.
Movement of Farm Equipment on Public Roads, Catalog
#69941-0013, for sale by the National Safety Council, 1-800-621-7615
Publication #: Pm-1563e
This Fact Sheet is apart of
a series from the Safe Farm Program, Iowa State University Extension,
Ames, Iowa. Safe Farm promotes health and safety in agriculture.
It is funded by the National Institute for Occupational Safety
and Health (NIOSH #U05/CCU706051-03), Iowa State University,
and a network of groups that serve Iowa farm workers and their
families. Publication date: September 1994.
by Mark Hanna, extension agricultural engineer; Charles Schwab,
extension safety specialist; and Laura Miller, extension communications,
Iowa State University Extension, Ames, Iowa.
Disclaimer and Reproduction Information: Information in
NASD does not represent NIOSH policy. Information included in
NASD appears by permission of the author and/or copyright holder.