Bringing Clarity to Barricades, Barriers, and the Evolution of the Longitudinal Channelizer

Posted by Tracy L Connors on

A graphic with two photos. One photo showing plastic barricades on a city street with chain link fence on a rainy day with a car turning onto the street. The other photo shows concrete barriers in the middle of the highway on a grey day. The images are surrounded by an orange frame.

For those outside the traffic control industry, the various types of temporary traffic control devices used in work zones are often a mystery. In this article, we break down the two primary categories: barriers and barricades, explaining their distinct roles in keeping work zones safe.

Understanding Traffic Barriers

Barriers are essential for protecting road workers by physically separating them from oncoming traffic. These robust devices, like the commonly seen concrete Jersey Barriers or steel-reinforced plastic barriers, are designed to redirect vehicles away from the work area. A key feature of these barriers is their ability to withstand impacts without allowing vehicles to break through the line, thus ensuring worker safety.

What Are Barricades?

Unlike barriers, barricades are primarily used to inform and guide drivers, channeling traffic away from active work zones. These lightweight devices, such as traffic drums and Type I barricades (commonly recognized as “sawhorses”), are designed to be non-threatening to vehicles in case of accidental impact. Typically, they feature white or orange colors with reflective materials to enhance visibility at night, making them effective channelizers in low-speed areas.

The Evolution of the Longitudinal Channelizer

In the 1990s, the industry witnessed the introduction of hollow plastic barriers, mimicking the look of traditional concrete barriers. However, testing quickly revealed that plastic barriers, even when filled with water, did not provide the necessary protection due to their lower weight and lack of strength compared to concrete. To meet safety standards, manufacturers began reinforcing these plastic barriers with steel—either internally with steel cables or externally with an exoskeleton. While this innovation passed safety tests, it introduced new challenges, such as increased deflection during impacts, requiring greater spacing from the work zone, which is often impractical.

Despite these limitations, the imposing appearance of plastic barriers proved highly effective in channeling traffic, leading to their evolution into what we now know as longitudinal channelizers. These devices are now widely used in various scenarios, from parking lots and pedestrian management to site security, often enhanced with chain link fencing for additional protection.

Conclusion

As the traffic control industry continues to evolve, the need for clear distinctions between barriers and barricades remains crucial for ensuring safety in work zones. Whether it’s protecting road workers or guiding drivers through complex construction areas, understanding the purpose and proper use of these devices is key. The development of longitudinal channelizers highlights the industry’s commitment to innovation, finding new ways to balance safety, practicality, and effectiveness in an ever-changing landscape. By staying informed about these advancements, both industry professionals and the general public can contribute to safer and more efficient roadways.

What is the Rotational Molding Process?

Posted by Remcon Plastics on

What is rotational molding used for?

Rotational molding (commonly referred to as rotomolding) is a manufacturing process that is ideal for making hollow parts.

What is the rotational molding process?

The rotational molding process allows you to form a plastic part by coating the inside of a hollow mold with plastic material. Plastic, usually in powder form, is placed inside a metal mold and falls to the bottom forming a pool. The mold is then put in an oven and heated until the plastic melts enough to become sticky and cling to the surface.

The mold begins rotating as it enters the oven like a rotisserie except you are rotating the part on two separate axes (think of it as a merry-go-round riding on a Ferris wheel). Because of gravity the plastic wants to slide to the lowest area of the mold. Since the mold is turning the plastic keeps sliding downhill and as the powder moves over the hot mold surface another layer of particles melts in to the wall that is forming. When all of the powder has dissolved in to the walls it is time to cool the part back down and remove it from the mold.

While the mold is rotating, the plastic, driven my gravity, slides to the lowest point. The biaxial rotation (merry-go-round on a Ferris wheel) ensures that every area of the mold passes through this low point and another layer plastic adheres to the mold surface. You continue to cook the part in this manner until all of the plastic has attached to the mold.

What are the steps involved in the rotational molding process?

There are four primary steps to the rotational molding process:

  • Charging the mold with the appropriate weight of the required raw material
  • Melting the material and spreading it around the mold
  • Cooling the part so that it returns to a solid state
  • Removing the part from the mold and performing any necessary trimming operations.

What materials are used for rotational molding?

90-95% of rotationally molded parts are made from polyethylene in a full range of densities. In addition, rotomolders have had success with PVC , Polypropylene, nylon, fluorocarbons (think Teflon), PFA.

Check out this video to watch the rotational molding process in action!