What it does:

Energy Absorption:

The core function is to absorb the kinetic energy of a collision, preventing it from being transferred to the impacted vehicle or structure.

Controlled Stop: By absorbing the energy, the TMA brings the impacting vehicle to a controlled stop, rather than a sudden, potentially dangerous impact.
Crash Protection:

TMAs are designed to protect both the impacting vehicle (and its occupants) and the object they might have collided with (like a barrier, bridge support, or work zone personnel).

How it works (specifically for an SST TMA):

Crushable Cartridges:

The SST TMA often uses lightweight aluminum cartridges within a steel support frame.

Controlled Crushing:

When impacted, the steel support frame is designed to collapse and the aluminum cartridges crush, absorbing the energy of the impact.

Reusable Components:

Some components, like the steel support frame, may be designed for reusability after a design impact.

Anti-Rotational Dampeners:

The SST TMA also incorporates anti-rotational dampeners to help maintain the correct impact position during a collision, further enhancing safety.
Where it's used:

Highways and Roads: TMAs are frequently used on highways and roads to protect workers and drivers from collisions with stationary objects like guardrails, bridge supports, or construction zones.

Work Zones: They are essential in work zones to shield workers from errant vehicles.
Other Applications: TMAs can also be found in various other situations where impact protection is needed, such as at toll booths or other areas with high potential for collisions.

The Iowa Department of Transportation is offering for sale used trailer-mounted attenuators (TTMAs), including the widely recognized Safety Trailer Inc./Gregory TTMA-100 models.
These units are being retired from our fleet as part of our commitment to align with the latest federal safety standards outlined in the Manual for Assessing Safety Hardware (MASH-2016). Iowa DOT Specification 4188.01 B.5. requires that all truck- or trailer-mounted attenuators used on state roadway construction projects be MASH-2016 compliant by December 31, 2029. To ensure our equipment continues to meet current and future safety expectations, we are phasing out older models in advance of this deadline.
While these trailers will eventually no longer meet Iowa’s evolving compliance standards for highway use, they may still hold value for a variety of purposes. Buyers outside Iowa should consult their local or state regulations regarding MASH-2016 implementation before using the units for roadway safety applications. Beyond their original use, many of these trailers offer a sturdy foundation for creative repurposing — from training use, mock setups, or even custom projects like mobile workstation, etc.

We believe in transparency and safety, and we also recognize that these units can continue to serve the public in other ways. If you’re a contractor, fabricator, or innovator looking for a solid platform to build from, these TTMAs may be just what you need.