Buying Guide

As the nation advances and new developments are being made each day, our highway infrastructures must improve along with it. Highway maintenance and the rehabilitation of existing roadways is a constant presence that has created work zone areas across America. Improving our roadways, bridges and streets will benefit all drivers by enabling safer means of transportation, however oftentimes the work zones themselves create vehicular hazards in the process. This article will explore the safety benefits of Longitudinal Channelizing Devices (LCDs) as an alternative to temporary concrete barriers (TCBs) for work zone traffic channelization.

3-29-13-traffic-safety-two-285x100

TCBs have been the exclusive solution to ensuring safe construction sites over the years, but these heavy concrete slabs pose danger when met with any vehicular contact. Concrete creates high gravitational forces that when impacted by an oncoming motorist, can cause serious harm or death to those inside the vehicle.

The main difference between LCDs and TCBs is the concept of shielding and preventing. TCB’s is a rigid and compact concrete slab that is designed to prevent the vehicle from entering a work zone as opposed to shielding it from a collision with a dangerous object. You’re probably thinking “but they both sound like bad situations” and you’re exactly right. This leads us to the presiding issue. LCDs and concrete barriers are two separate devices that serve two very different purposes, and they are often placed in the wrong areas, leading to very dangerous (and sometimes fatal) misuse.

Aframe-rail

As of now, LCDs have only been used to outline pedestrian travel paths around traffic zones. However there are many other purposes LCDs could serve that they aren’t considered for, such as replacing concrete barriers to close roadways from vehicular traffic. Closing roads using a TCB demonstrates its frequent misuse, because concrete barriers placed at such a high angled impact zone is extremely hazards to drivers.

LCDs could safely replace TCBs in this sort of work area because high level protection isn’t required. Unlike concrete, they are designed to give way and allow a vehicle to pass through the device, in turn keeping an impact tolerable to the human body. Ultimately, using a high impact device in a low impact area breeds hazard creation as opposed to prevention, as quoted by the American Association of State Highway and Transportation Officials (AASHTO)

..a barrier should be installed only if it is clear that the result of a vehicle striking the barrier will be less severe than the crash resulting from hitting the unshielded object itself.

Additionally, in contrast to traditional tools such as plastic cones and drums that create open space between devices, LCDs can be connected together to form a solid line. This prevents both drivers and pedestrians from going through these open spaces and entering the work area.

LCDs can also serve as a highway lane closure and replace cones and drums as a form of merging device. Although the LCDs will be spaced apart, their large size combined with a continuous positioned line will make them appear to be a solid lane closure.

LCDs’ large size also makes them highly more visible than cones and drums, which not only allows for increased spacing (fewer devices would be needed) but also increased sight and distance recognition from drivers.

The above examples are just a few of the minor previsions that could be made as a result of utilizing LCDs. These lightweight, deformable devices are more affordable than concrete and could safely delineate our vehicles and pedestrians from countless work zone environments. A proper consideration of their benefits will bring about positive results for those involved in any transportation scenario.

crosswalk_-1140x445

The widespread use of concrete barriers has predominately been used for channelization (to divert traffic away from the work site and its workers) as opposed to positive protection for motorists as well. This is why over 85% of fatalities occurring in work zones are that of drivers and passengers.

When determining the safest choice for TTC (temporary traffic control) in a work zone, one should evaluate devices that have equally balanced protection in mind. This means both road maintenance workers AND the road users who are traveling through said work zones.

That being said, concrete barriers are only made to deflect a vehicle’s penetration into the work site and potential injury to its workers, but does more harm than good to those inside the vehicle.

Once again, using a concrete barrier as a channelization device, whether it be in a work zone or to close roads, is extremely dangerous. Concrete barriers are massive solid objects that aren’t designed to soften the blow of an impact and ultimately expose vehicles and their occupants to injury or death.

Plastic LCDs are more innovative and effective mechanisms for specific traffic control jobs, especially those associated with channelization. The continued reliance on concrete barriers for every work zone application is dangerous and unnecessary. Additionally, concrete barriers require a flat bed and crane during installation. Not only does this result in an added time constraint and expense, it also creates more traffic congestion. Plastic LCDs are lightweight and can be unloaded manually without compromising an additional lane during installation.

drums

MUTCD (Manual on Uniform Traffic Control Devices) reaffirms this notion in its description of channelizing devices:

Channelizing devices should be constructed and ballasted to perform in a predictable manner when inadvertently struck by a vehicle. If struck, they should yield or break away, and fragments or other debris from the device should not penetrate the passenger compartment of the vehicle or be a potential hazard to workers or pedestrians in the immediate area

(http://www.osha.gov/doc/highway_workzones/mutcd/6f_typesofdevices.html)

The above passage confirms that channelization devices should be light enough to break away on impact, not remain solid and obstruct the oncoming vehicle. Ultimately, plastic LCDs create a more positive outcome for motorists in the event of a collision in comparison to a traditional concrete barrier.