Footer Text Date

TMA BEST PRACTICES:COMPLACENCY VS. AWARENESS2018 Transportation Short Course

October 17th, 2018

Early TMA (1980)

2

Examples of Truck Mounted Attenuators (TMA)

3

Positioning the Attenuator Proper positioning of the TMA vehicle

within the work zone is critical to its effectiveness.

The TMA vehicle location should provide sufficient warning to approaching trafficand maximum protection for workers.

• Too close to the work when hit, it may strike workers.

• Too far back, traffic may go around it and hit workers.

• Consider tightening cones on tangent to prevent incursion into the work zone.

4

Positioning of the TMA in the Work Zone

The shadow truck should be positioned a sufficient distance in advance of the workers or equipment being protected….

Roll Ahead Distance (RAD) is the distance the TMA / TTMA will move, or displace, when struck.

– Refer to your Traffic Control Plan

– In accordance with TCP General Notes for Stationary Operations (i.e TCP 1 & 2 series):

• “A TMA should be used anytime that it can be positioned 30 to 100 feet in advance of the area of crew exposure without adversely affecting the work performance.”

• The minimum distance the TMA will be placed in advance of the work crew is 30 feet.

5

Mobile Operations If you are operating a TMA truck, your

job is to protect the crew and yourself.

– If you notice an errant vehicle coming towards your TMA truck Do not leave your lane of traffic –shield the crew!

– If you abandon your position this would expose the crew to a crash and possible injury.

• Alert the crew!!

• If impact is imminent, prepareby placing your head againstthe headrest to reduce injury.

6

Stationary OperationsWhen protecting the work crew at a stationary job site, the strobes must be activated, the arrow board working, and the TMA must be fully deployed. No vehicles or equipment are allowed in roll-ahead space or in the buffer space.

With the TMA at the beginning of the work activity area, the following recommendations should be followed:

Wheels turned away from the work crew and work activities,

Whenever possible, wheels should also be turned away from the crew’s escape route,

Emergency brakes are set,

Standard transmission units placed in gear,

Automatic transmission units placed in park, and

The TMA unit is unoccupied and not occupied again until repositioning is necessary or the work zone is being removed.

7

Roll Ahead Distances—Impact by 80,000 lb Semi Truck

8

Roll Ahead Distances—Impact by 80,000 lb Semi Truck

9

TMA Best Practices

Two years ago ELP implemented a mandatory training for all TMA operators on CST and MNT contracts.

In the last two years, over 500+ employees have been trained on proper TMA use and practices.

Each operator trained, is issued an identification card which allows them to work on ELP projects.

They are all empowered to call a “time out” as are the rest of our TxDOT employees if something doesn’t “feel” right in the work zone.

10

New MASH Standards

New MASH Standards only apply to Federally funded jobs on the National Highway System (NHS).

Existing TMA’s meeting NCHRP-350 standards may be used throughout their “useful life”

But…shouldn’t we try to evolve more quickly as standards change?

11

New MASH Standards

As of last night, there are only three TMA’s approved by the FHWA that meet new MASH Standards.

–1. Scorpion II Trailer Attenuator--Traffix

–2. Scorpion II TMA--Traffix

–3. Blade TMA--Verdergro

12

Scorpion II Trailer Attenuator

13

Scorpion II TMA

14

Blade TMA--Verdegro

15

The Future of Work Zone Safety

Autonomous TMA’s

Work Zone Intrusion warnings

16

TMAs and TTMAs Work

17