Road work is a hazardous thing in itself, one most people don’t think about until they see a traffic cone and wonder what’s going on. The truck behind a mobile work zone (with a large yellow crash cushion mounted on the back) is working harder than most people realize. This is a TMA and if you are in charge of road works, you are likely to have looked for a TMA truck on rent rather than purchasing a truck outright, and that is usually the better idea.
This guide explains what a TMA is, why renting is an important consideration for most contractors, what the UAE calls for and what to check before signing a rental agreement.
The Functions of the TMA Truck Mounted Attenuator Available on Rent
A truck mounted attenuator is an energy absorbing device attached to the back of a maintenance or work zone vehicle. The role of its job seems too easy: If a vehicle collides into the back of it, it absorbs the impact energy and reduces the collision speed rather than transmitting the entire impact force directly to your crew and equipment. It essentially makes a potentially deadly rear end collision survivable for the driver who made the error, as well as the workers in front.
The units are placed on trucks which follow the mobile operations such as line painting, pothole repair or lane closing, and operate at the same speed as the mobile unit, not static. They are also used at static work areas, where they are parked at the rear of a work site before traffic can reach the work area.
There are Many Reasons Why Renting is a Better Option than Purchasing
Having a TMA equipped truck on the bottom line is a substantial capital investment and most contractors aren’t in need of such a machine year-round anyway. Road projects change, contracts last differently, and when your truck’s not working, it’s still costing you insurance, storage and depreciation. Flips the equation with rentals. You pay for the equipment when a project calls for it, and you don’t have to keep up with special, crash-test equipment between projects.
Renting also has a compliance angle which solves it in a quiet and efficient manner. TMA units are crash-tested, but as newer standards are adopted, the older standards are no longer relevant and a good rental company ensures they have current units. Now there’s just one less item on your list as a contractor with five other compliance documents for one road permit.
The Safety Aspects of Every TMA Truck Mounted Attenuator Available on Rent
But this is where it gets technical—it does matter, so hang with me for a little bit. The TMA’s are crash-tested to meet standards established in the National Cooperative Highway Research Program Report 350, or the newer Manual for Assessing Safety Hardware, referred to as MASH. The majority of units that were produced since January 1, 2023, must comply with the MASH 2016 Test Level 3 crash test requirements, and the majority of non-MASH 2016 units manufactured prior to January 1, 2023, can continue to be used for a certain period of time.
Test Level 3, or TL-3, is applied to attenuators that are designed for higher speed impacts, making a huge difference on high-speed highways. Typically, a TMAs that meets MASH or TL-3 rating specifications can withstand impact at speeds of approximately 62 mph. That one speck makes the difference between a piece of equipment that can keep your crew safe on a highway and one that is only rated for an urban road.
If you are renting, check to see which standard the unit meets, and ask for the manufacturer’s certificate of approval. A reputable rental firm will give this to you freely since it is a piece of paperwork you’re going to require when you’re applying for your own road registration.
The UAE’s Regulations Require It
In Dubai, TMA requirements are not just a formality of documents that you have to submit, but a key part of the process of how the Roads and Transport Authority assesses your traffic diversion plans. RTA’s traffic diversion drawing guidelines require that a TMA be indicated on the layout drawing and that it be tested at both MASH and NCHRP 350 Test Level 3, but that it be tested for TL-3 only in the category of 80 km/h and above. A lower-rated attenuator won’t get approved if your project is located on a high-speed arterial road.
In addition to the equipment spec itself, RTA’s Right of Way permit process requires an approved traffic management layout, the appropriate safety equipment according to the Work Zone Traffic Management Manual, and site documentation before work is allowed to commence, as outlined in the Executive Council Resolution No. 54 of 2021 (works in the right of way). Abu Dhabi has its own version, with the emirate-specific process detailed in its Temporary Traffic Management Manual, but the safety principles remain the same in both cases.
The key here to remember is that you don’t want to wait until your permit is rejected to determine what your TMA specification will be. Before you call rental companies, check the road test level for your particular highway.
Before You Rent, You Should Consider the Following
If a truck is cheap, but arrives without the proper paperwork certifications or an attenuator that is dented and was previously crashed without anybody checking, it is not a cheap truck. Prior to committing, inquire if the provider can provide the crash-test certification that meets the standards required by your project, the unit has been inspected and is not damaged by a previous impact, and the attenuator and arrow board controls are operable from within the cab (which is how the driver is supposed to control safety on today’s units).
Also check to see if amber warning lights on the vehicles are required to be seen from all 360 degrees around the truck, and not just from behind. If a unit is unable to provide this basic feature, it’s a unit that you should walk away from, regardless of how good the price appears to be.
Inquire also about turnover time and back-up availability. Rarely will road projects go on time and when your rented TMA truck breaks down in the middle of a project, you need a provider who can replace it quickly instead of leaving your crew vulnerable for a day while paperwork gets sorted.
Picking the Right TMA for Your Project
Not all jobs require the same configuration. A lower speed of travel in an urban setting than a higher speed of travel on a highway has different needs than a mobile operation that travels slower than a static work zone. While static setups are set up at a fixed location and are usually subject to the approach speed head-on, mobile TMA trucks follow the actual work crew and must maintain a safe following distance without engaging in the work as well. It is important to be honest with the rental party about your project type (don’t ask for “a TMA” as that defeats the point of an altitude and distance meter!)
The Rental Process Smooth TMA Truck Mounted Attenuator Available on Rent
If the correct specification has been verified, the actual rental is typically a fairly simple procedure. Most good UAE-based providers can provide documentation within a reasonable time to submit to the RTA or municipality, so plan ahead to ensure you have it the week prior to your project and do not request it the last week of the job. The other thing that good providers will do is walk your driver through the unit specifics – not all TMA trucks are created equal, and a five-minute walk-through in the first day saves a lot of money!
The Bottom Line on TMA Truck Mounted Attenuator Available on Rent
A TMA truck with attenuators (on rent) is an effective, compliant solution for protecting road crews without a long-term investment in attenuators. But it’s not just the equipment that matters. Allows the project to get underway rather than getting stuck on the permit stage by matching the proper MASH or NCHRP 350 test level to the speed limit of the road, verifying the certification before it was submitted, and knowing exactly what the local RTA or municipality wants from the permit in paper. Have the groundwork covered, and the truck behind your work zone does exactly what it’s meant to do: provide your crew, and all those drivers following them, a fighting chance.