TMA Trucks, Attenuators, and Safety Products: An Overview

New to work-zone safety equipment? This overview covers the main pieces, how they fit together, and where to start.

Work-zone safety equipment can look like a jumble of terms: TMAs, attenuators, arrow boards, message signs, pavement markers. They all serve one goal, which is keeping crews and drivers safe where the road narrows. Here is how the main pieces fit.

The TMA truck and attenuator

The centerpiece is the TMA truck, sometimes called a crash truck. It parks behind the crew as a shadow vehicle. Mounted on its rear is the attenuator, the crash cushion that absorbs an impact if a driver fails to stop. Attenuators come in non-blade designs like the Scorpion and blade designs that use crumpling blades. Each is rated to a MASH test level, TL-2 or TL-3, based on speed.

The signaling equipment

• Arrow boards, in 15-lamp and 25-lamp sizes, direct traffic out of a closed lane
• Changeable message signs display text to warn and inform drivers
• Raised pavement markers keep drivers in lane at night and in rain

Where to start

Start with the attenuator test level, because it is set by the speed of your work zones. Then choose a chassis with enough GVWR to prevent underride, around 26,000 lb or more. Add signaling based on the closures you run. You can buy, rent, or lease the result, and have it repaired and re-certified when the time comes.