There Are Various Kinds of TMA Truck Mounted Attenuators Available in UAE, and These Are Listed Below
Not all Truck Mounted Attenuators are created equal, and one of the most costly errors a contractor can make is to assume that “a TMA is a TMA”.
There are various speeds, mounting methods and energy absorbencies, and if you don’t choose the right one for a UAE highway project, you end up with a device that doesn’t do what you need.
This guide provides an overview of the main types of TMA truck mounted attenuators used in UAE road and construction projects and the difference between them.
This Book Provides Detailed Information on the Different Types of Classification
TMAs are not divided into brand divisions, or even toughness divisions.
They are divided into three types depending on their ability to survive.
A TL-2 attenuator can be qualified and tested for an impact vehicle of a certain weight to stop the vehicle at approximately 70 km/h, a TL-3 attenuator can be qualified and tested for an impact vehicle of a certain weight to stop the vehicle at approximately 100 km/h.
This is the only difference between Test Level 2 and Test Level 3 that influences nearly all the other choices a contractor makes regarding equipment installation.
Do it wrong, and you end up paying for protection that you don’t need, or worse, underprotect a crew that is close to fast moving traffic.
TL-2 Attenuators Have Been Designed for Moderate-Speed Zones
TL-2 is the level at which serious work zone protection begins, but rather than an economy compromise, it’s a match to a different risk profile.
The TL-2 attenuators are intended to be used in moderate impact zones and generally are the more economical choice for moderate impact settings.
TL-2 attenuators are used to provide life saving protection in work zones up to 70 km/h.
Consider city streets, slower arterial roads or areas where speed limits are already set and are lower.
TL-3 Attenuators: High Speed Standard
TMA Truck mounted attenuators UAE
TL-2 does not suffice for UAE highways, such as Sheikh Zayed Road, Emirates Road and others, which are high speed roadways.
Although TL-3 attenuators may have a higher upfront cost, they offer greater safety features for high-speed roads with dangerous traffic, and are the recommended choice for these types of roads.
TL-3 protection can be used for high speed work area up to 62 mph (100 km/h).
In the UAE, unless you’re working on a very serious roadwork project, TL-3 is usually the minimum you can expect for most major highway projects, and not something to reserve for the “high-end” projects.
It’s important to note that there’s some nuance in the TL-2 and TL-3 categories.
Some manufacturers provide a “TL-2 Plus” rating, aimed specifically for cities, counties and urban districts that have speed limits of 50 mph (80 km/h) or less.
This intermediate speed can be helpful for urban roadwork in the UAE that falls between slow city and fast highway speeds.
There Are Two Different Approaches: Truck-Mounted and Trailer-Mounted
The next big decision to be made is how the attenuator is to be mounted in the host vehicle other than speed rating.
There are 2 main configurations and each one is appropriate to different operational needs.
A genuine truck-mounted attenuator is connected directly onto the truck’s frame.
The TMA can be applied to advanced warning vehicles, stationary block vehicles, and moving shadow trucks upstream of the work zone.
This configuration is usually the best choice as the attenuator is a part of the host truck.
Attenuators with a trailer mounted on them are a different form of flexibility.
Attenuators that are towed are attached to a truck, and they don’t need to be installed in the host vehicle.
A range of host vehicle weights can be supported effectively and trailer mounted attenuators can be used both stationary and moving.
It does matter for UAE contractors that go from one type of vehicle to another, or to rent trucks for various projects.
A unit on a trailer will not require any long-term modifications to a fleet of trucks and a totally truck mounted unit will provide more integration for dedicated TMA vehicles.
This Activity Is Designed to Explore the Concept of Energy Absorption Mechanisms, What Is Really Going on in the Unit
Now, things get interesting from an engineering perspective.
The speed rating lets you know what a TMA can withstand, the absorption mechanism tells you how.
The aluminium honeycomb structures are used in many modern TMA cartridges as their collapse is highly predictable and progressive and energy is absorbed equally at a wide range of temperatures.
This uniformity of temperature rings especially true for the UAE where asphalt and ambient temperatures are a common stress on equipment during the summer months.
In some systems, energy absorption is achieved by the action of replaceable aluminium tubes contained in a moisture-proof cartridge, and by hydraulic rotating mechanisms which enable the cartridge to be raised or lowered as necessary.
This type of modular design allows for easy replacement of a damaged cartridge, which would otherwise need to be replaced with a new one after an impact.
Hydraulic systems also have a structural function other than absorption.
A hydraulic system can be used to lift the TMA cartridge partially up for maximum roadway clearance and manoeuvrability, while the unit crushes in progressive stages on impact to absorb the crash energy in a controlled manner.
Other absorption principles have been employed in older designs or alternative designs.
The early designs of crash cushions incorporated a chamber filled with crumpleable plastic foam and plastic deformation of the sheet metal to absorb the kinetic energy of the impacting vehicle, or compressed air which is used in a manner similar to that of a spring to generate an increasing resisting force against the impact vehicle.
There is also a new category of water-based systems.
Water-based crash cushions work mainly in the manner of momentum transfer, that is, the momentum of the vehicle impact is transferred to the water which spreads out at high speeds and the containment modules break upon impact.
Aluminium honeycomb and hydraulic tube dominate the modern TMA market in practice as they offer the advantages of reusability, predictability and serviceability after an impact — a critical requirement for contractors who are not willing to add significant downtime to their bills.
Functional Add-Ons That You Should Know About
TMA Truck mounted attenuators UAE
Modern TMAs are not simply a cushion that is bolted to a truck.
They tend to be packaged with visibility and operational characteristics which actually have an impact on performance.
Common functional features include:
- Left and right arrow boards
- Alternating LED corner lights
- Integrated LED taillights
- Double safety blocking devices
- Forklift pockets for easier handling and repositioning
Some units take it one step further in the safety-engineering department.
Some TMA models can also be connected to the automatic brake system of the host vehicle, which activates the brakes in the event of a collision, providing an additional layer of safety for the TMA driver, the driver of the vehicle involved in the accident and for any workers in the nearby area.
These features are not just marketing hype; they directly impact the safety of the TMA’s performance and efficiency in the field, particularly during conditions of poor visibility, such as dust storms or nighttime operations.
Tight Conditions Are Catered for With Specialised Designs
Not all UAE work zones are spacious enough.
Standard TMAs will not always work on low underpasses, parking structures or other urban sites with tight restrictions.
Some TL-3 TMAs are angled 180 degrees with a special tilt mechanism for storage and low underpasses to provide maximum protection in minimum length, weight and height.
Other low-profile designs feature an open tubular structure, resulting in lower wind resistance and drag and thus safer high speed travel between sites.
These are more suitable to use in areas where overhead clearance and manoeuvrability may be as critical as crash protection for contractors operating in high-density urban centres in Dubai or Abu Dhabi.
Selecting the Appropriate Type of Project for UAE
Combining all these, some basic considerations come into mind.
For high speed road construction, which most of the major construction projects on the UAE’s roads is, TL-3 should not be considered an upgrade, but a standard.
A TL-2 or TL-2 Plus unit may be more cost effective and still provide adequate protection if the roadwork is performed at a slower speed in an urban area.
Trailer mounted can be used by contractors in a diverse range of vehicle types, and purpose built TMA vehicles are integrated systems.
In either installation, make sure that the absorption mechanism, the level certification of the test, and the accompanying visibility features are checked before committing to equipment.
Truck-Mounted Attenuators are still one of the most important items of safety equipment in today’s work zone — and choosing the right type is the only way to ensure that it works when it is needed.
Final Thoughts on TMA Truck mounted attenuators UAE
Choosing the correct Truck Mounted Attenuator is not simply a matter of selecting any crash cushion available.
Understanding the differences between TL-2, TL-2 Plus, and TL-3 ratings, truck-mounted and trailer-mounted configurations, energy absorption technologies, visibility enhancements, and specialised low-profile designs allows contractors to select the right equipment for the right application.
For UAE contractors working on road construction, maintenance, utility installations, and infrastructure projects, the right TMA can mean the difference between compliance and non-compliance, between protection and exposure, and ultimately between a safe work zone and a dangerous one.