Solution Summary: Movable Longitudinal Barriers
Movable longitudinal barriers, like the Mobile Barriers MBT-1®, are engineering control solutions that can help eliminate work zone struck-by injuries. These barriers are essentially long trailers that can be pulled fully set up by any standard semi-tractor with 60” of swing clearance and at least a 20,000 pound capacity.
Under the U.S. Department of Transportation Federal Highway Adminstration, these patented barriers (U.S. Patent 7572022, 7901117, 8322945, and 8465047 [patents pending]) are classified as "longitudinal barriers." They are rigid wall trailers that can be extended up to 102 feet in length and has over 2,000,000 pounds of shear strength with the ability to stop a vehicle in a direct 90 degrees impact of at least 60 mph. Per the manufacturer Mobile Barriers LLC, there are currently 20 MBT-1® in the U.S. (4 in other countries) in which they may be rented or leased with the option for purchase as well commensurate with project goals and overall deployment strategy. For more information on their numerous flexible payment options, please contact the manufacturer.
They have a work area and storage compartments on one side and a barrier on the other side. Thus, this bidirectional feature allows the trailers to be easily reconfigured to the left or right depending on the end to which the tractor is attached. Further, the MBT-1® can be customized with integral power (120/240 generator, 12/24V batteries & solar), lights, truck-mounted attenuators (TMA), and signage (figure 1).
Figure 1. A deployed MBT-1® with integral power and lights at a night time construction job (Source: http://www.mobilebarriers.com/night_stills.html)
Working in road construction sites has an increased risk of work zone struck-by injuries and fatalities. Based on preliminary CFOI data, there were 116 work-related fatalities at road construction sites in the U.S. in 2014. In The Construction Chart Book 5th edition published by CPWR, Chapter 46 show vehicles were the source of more than half of the fatalities at road construction sites - double the proportion of such deaths in the overall construction industry from 2008 - 2010 (graph 46b). Among fatalities involving vehicles and heavy equipment at road construction sites, most were workers on foot or non-passengers who were struck by vehicles or heavy equipment in the work zone or passing vehicles that entered the work zone. Deploying movable longitudinal barriers can eliminate the risk of struck-by injuries in work zones.
How Risks are Reduced:
The MBT-1® primarily eliminates the risk of work zone struck by injuries by providing a barrier shielding workers from traffic. Further, they can also help improve safety while reducing the number and duration of lane closures which enables construction road work to be done quicker and reduces the time exposure workers need to be in work zone areas.
The MBT-1® also incorporates work zone lighting systems to reduce the risk of injuries and accidents by helping to ensure that adequate lighting is provided in work zones. Using trailer mounted lights, light towers, or balloon lighting will greatly increase awareness of surroundings and create an easier work environment in which to maneuver.
Per the National Cooperative Highway Research Program crash test, the performance of the Mobile Barrier Trailer was found to have sufficient capacity to contain and redirect an impacting 2,329kg pickup truck safely under Test Level 3 conditions, (traveling approximately 62 mph at an angle of 25 degrees). For more information, please view the report here. Further, the U.S. Department of Transportation Federal Highway Adminstration acceptance letter, states that "the MBT is a semi-rigid vertical wall with relatively low friction characteristics that can be favorably compared to vertical concrete barrier walls that passed prior full-scale testing."
To learn more about work zone lighting and ambient conditions, please visit the detailed solution Work Zone Lighting.
Effects on Productivity:
Per the claims by the manufacturer Mobile Barriers LLC, using the MBT-1® reduces the number and duration of lane closures which can increase productivity by allowing workers to focus on finishing their work zone tasks quicker. Further, because these temporary barriers can be pulled fully set up, it is much quicker to deploy than setting up concrete Jersey barriers which can require continuous rigging and lifting by heavy equipment.
Conditions providing high illuminance show improved performance of cognitive work tasks. Workers who feel safe will, in return, perform more efficiently (Boyce, 1997).
It is recommended to follow all manufacturer guidelines before using this equipment to ensure worker safety and compliance with applicable local, state or federal regulations.
In addition, it is recommended that all work zone workers don high-visibility safety apparel. To learn more, please visit the solution High-Visibility Safety Apparel.
Le, Jean Christophe, MPH - CPWR The Center for Construction Research and Training
This solution page was adopted from information found on the Mobile Barriers website: http://mobilebarriers.com/
Boyce, P.R., J.W. Beckstead, N.H. Eklund, R.W. Strobel, and M.S. Rea. "Lighting the Graveyard Shift: The Influence of a Daylight-simulating Skylight on the Task Performance and Mood of Night-shift Workers." Lighting Research and Technology 29.3 (1997): 105-34. Lighting and Resource Technology. SAGE Journals. Web. 11 July 2013. http://lrt.sagepub.com/content/29/3/105.short
NIOSH Workplace Solutions Sheet
The National Institute of Safety and Health (NIOSH) has published a series of “Workplace Solutions”, which are easy-to-understand recommendations from NIOSH research results. Related to this Construction Solution, please find more information on: Preventing Worker Injuries and Deaths from Backing Construction Vehicles and Equipment at Roadway Construction Worksites