In 2011 and 2012, a number of Kentucky Amishmen landed in jail for not carrying an SMV safety triangle on their buggies.

This story got major news attention across the nation. State law was eventually altered to allow reflective tape instead of the triangle, thanks in part to 138 hand-written letters sent by an Amishman to Kentucky legislators.

While the vast majority of Amish use the triangle, a minority do not, notably the Swartzentruber Amish. This lack of a triangle has led to fines, criticism, and as we saw in Kentucky, even imprisonment.

SMV Triangle Problems

Not as helpful as we think?

The assumption has often been that the SMV triangle is a necessary–even the best– safeguard providing road visibility. Without an SMV triangle on the buggy, the thinking goes, you are endangering not only yourself but motor vehicle operators.

In a new paper in JAPAS, “Horse and Buggy Crash Study II: Overstretching the Slow-Moving Vehicle Emblem’s Abilities: Lessons from the Swartzentruber Amish,” Cory Anderson investigates this assumption.

His analysis leads to some interesting and even surprising conclusions.  You’ll want to read the discussion in full, but I’ll share some of the main points here.

Shortcomings of the SMV triangle

Anderson first reviews the background of SMV triangle usage among Amish, and then analyzes the different indicators that alert drivers to the presence of the buggy.

It is important to note that this analysis focuses on one aspect of buggy visibility–conspicuity, which as Anderson states is the only purpose of the SMV triangle. Illumination and obstruction from view are two separate issues which the SMV triangle does not address.

These conspicuity indicators are the triangle, reflective tape outlining the back borders, and the buggy itself.  These can be looked at alone, or in different combinations. Anderson looks at each individually for simplicity.

Cory Anderson JAPAS Buggy Safety Configurations

Figure 3 from Cory Anderson’s paper, showing different rear marking combinations

He makes a number of observations on the three. An obvious one that gets overlooked is that the buggy itself is an indicator, but that it is difficult to see by itself at night, at different times of day, and when obstructed.

Another is that at night, reflective tape is better than the small reflective perimeter of the triangle. And while he credits the orange center of the triangle as better than the tape at attracting attention, he identifies a number of problems with the emblem, including:

  • Does not convey info on how much to slow down.  When you approach an Amish buggy at speed, the “box” of reflective tape outlining the back borders grows larger to indicate a slower-moving object.  The small SMV triangle does not really convey this information.
  • Inconsistent appearance. The appearance of the triangle may vary depending on the time of day and distance.
  • Inconsistently and illegally used.  People put SMV triangles on stationary objects, such as mailboxes or fences, counter to the law.  It’s also used on a variety of other vehicles (such as tractors or golf carts), but not always, depending on the state and vehicle.

Does the SMV triangle actually hurt?

Anderson also discusses the most common types of crash situations, including rear-strike collisions (when passing), side impacts, and crashes while buggies are making left turns.

Surprisingly, the SMV triangle may actually contribute to rear-strike collisions:

  • Draws attention to center, but does not convey width.  The SMV triangle draws our eyes to the center of the vehicle, but does not suggest how wide the vehicle is. This does not help in the common rear-strike collision while passing, and may even hurt (see “moth effect” below).
  • The “moth effect”.  This was the most surprising piece of information to me. As Anderson writes, “Crash analysts have observed that motorists tend to steer in the direction of a well-lit emergency vehicle on the shoulder at night. The idea is that the carnival of lights attracts too much attention, and the motorist is drawn towards it, like a moth to light in the night (Green 2006).”  The triangle teamed with tape and LED lighting may help create a similar result by “draw[ing] too much attention”.

Better solutions?

Anderson then hypothesizes on possible better solutions, particularly for preventing rear-strike impacts, including:

  • Tape and lantern. This combination indicates both dimensions of the buggy, and the left-most border of the buggy, potentially more helpful in passing situations. Given the moth effect, is the Swartzentruber pairing of single left-side lantern and reflective tape actually superior to the SMV/LED light combo more standard among Amish (at least in rear-pass situations)?
  • Left-mounted or split triangle. Some Amish already do this (for example, when towing a cart).  Splitting the emblem in half and placing a piece on each side would help convey width.  Hanging it on the left corner would indicate the furthest left dimension.

In his conclusion, Anderson states that while the triangle “may alert drivers to something going on”, it may actually be an “extra step” in processing the object as a horse and buggy.

Furthermore, the triangle “is weak in communicating to the motorist what it represents (a slow-moving vehicle) and how to respond.”  And when the motorist does know a buggy is present, such as in passing situations, the emblem is not effective–and may even hurt, given the moth effect.

What do you think? Does this surprise you? What has your experience been on the road with Amish buggies?