Modern Road Signs: Materials and Manufacturing Techniques
When it comes to modern road signs, the choice of materials is critical for ensuring their longevity, safety, and effectiveness. Roads in regions with harsh winters often face the challenge of de-icing salts, while other areas may require signs that can withstand various environmental conditions. This article explores the materials commonly used in road signs, focusing on aluminum, galvanized steel, plywood, and the reflective sheets that make them visible to drivers.
The Role of Materials in Road Sign Durability
Eastern Canada, for instance, heavily relies on salt as a de-icing agent during winter. The frequent exposure to salt can be highly damaging to the signs, leading them to deteriorate quickly. To address this, many modern signs in these regions are made from aluminum or plywood, which offer better resistance to the corrosive effects of salt. Aluminum is preferred for smaller signs near the road, such as speed limit signs, due to its lightweight and strength. Larger directional signs and announcements, however, frequently use plywood because it is more durable and can span larger areas without the need for extra bracing.
While galvanized steel is a common material for road signs, it may not be the best choice in areas with high salt exposure. Signs made from galvanized steel often show signs of rust even after just a few years, particularly if the coating is compromised. In cities like Ottawa, where a parkway still features some older signs, the dramatic pattern of rust through the paint is clearly visible, indicating the limitations of galvanized steel in such environments.
The Common Raw Materials for Road Signs
For most ground-mounted sheet signs, the base material is aluminum, covered with a reflective sheet overlay. This combination ensures that the sign remains visible under a variety of conditions, including bright sunlight, rain, and fog. The aluminum base is ideal because it is both lightweight and resistant to corrosion, although it does not provide the same durability in salt-heavy environments as other materials.
Galvanized steel is the most common base material for road signs. It has several advantages over aluminum, including cost-effectiveness and greater strength. Although aluminum never corrodes, galvanized steel can withstand harsh conditions over a longer period. However, galvanized steel can corrode significantly if the zinc coating becomes damaged, undermining its effectiveness. In contrast, aluminum remains stable regardless of environmental conditions.
The Importance of Reflective Sheets
The symbols on modern road signs are often made from a special plastic that contains small glass beads or microprisms for maximum reflectivity. These components ensure that the signs remain visible even when the light source is at an angle. The reflective sheets used on the signs can greatly enhance visibility, especially under low light conditions or in adverse weather. This technology is critical for maintaining the safety and effectiveness of road signs, ensuring that drivers can easily read and understand the information displayed.
In conclusion, the choice of materials for road signs is a delicate balance between cost, strength, and durability. By selecting the right materials, signs can continue to serve their critical function, ensuring the safety of drivers and the functionality of our roadways. Understanding the specific needs of various regions and environments is crucial for selecting the best materials and manufacturing techniques for road signs.