What Are The Yellow Grids On Telephone Poles For?

It's frightening to think just how different even the most familiar drives become in the dark. You didn't know that pothole was there? If you weren't coming past slowly enough to register its gaping presence ahead, you might well disappear down it. If that jogger hadn't been wearing that reflective gear, you may not have seen them crossing ahead of you. There are some vital safety tips you should bear in mind when driving at night. 

The fact of the matter is, no matter how big an obstacle or feature on the roads may be, if it doesn't produce light of its own, it's so easy to miss, and can loom out of the darkness at the last moment. Streetlamps illuminate themselves, but telephone poles typically don't, making them a huge potential hazard at night.

Not only is there a great risk posed to the occupants of a car, but harm to such a pole can have costly and far-reaching consequences for the community. To mitigate this problem, some poles have been equipped with a mysterious-looking yellow grid. Many have been confused by this adornment, but its purpose is clear (and very important): The idea is that it will make the pole more visible to drivers on nearby roads.

The thing about reflectors is that they don't emit any light of their own. For example, with the moon, it's the Sun's own light that we're seeing, but for these reflective grids, they're counting on the light from drivers' often very bright headlights.

The Philadelphia Electric Company is responsible for adding lots of these grid reflectors. In June 2012, PECO's Cathy Engel Menendez explained both their function and their form to CBS News. "We're hoping ... it will be much more effective at attracting drivers' attention to the utility poles," came the explanation, acknowledging that, as removing a pole and replacing it with another elsewhere could be impractical or costly, highlighting exactly where they are may work just as well. PECO started installing them in 2007, and by 2019, over 200,000 PECO poles had their older white reflective components replaced with these fetching yellow ones. 

To do their vital job more effectively, the key is to capture incoming headlights as well as possible, and so the shape of the reflector was carefully considered too. The grid in the name is a reference to its latticed pattern, which allows the reflective effect to work at a range of angles. This means that more vehicles, regardless of their size, how they approach, and other unpredictable variables, have a better chance to see the pole looming with enough warning to react and avoid disaster. It's a danger that is common enough to require such measures, and they can take a variety of different forms (as with the striped reflector pictured here).

As noted, reflective gear has surely saved many pedestrian lives on and around the world's roads. CERN reports that "visibility increases to ... 140 metres for reflective clothing and accessories," compared to only approximately 25 meters should somebody be wearing something dark. The general approach of grid reflectors, then, is one that can certainly be effective. The principle is also seen in other critical safety elements on our roads, primarily those differently colored cat's eyes and road signs, both of which can also cut costs and logistical problems by reflecting light rather than producing it.

On the specific subject of telephone and utility poles, a report from the Federal Highway Administration noted that "there were 854 average annual RwD fatalities between 2016 and 2018 where a utility pole was identified as the most harmful event." The report notes that illuminating such poles is one step that can make their placement less of a hazard for vehicles, and that there is a range of others that have been and can be implemented depending on location and feasibility. For instance, "New Jersey is using special fiberglass poles that are designed to collapse on impact instead of breaking away into active traffic."

In short, there are steps that can mitigate the harm of a potential collision, and there are steps that can contribute to preventing it in the first place. Those seemingly innocuous yellow grids and other patterns on telephone poles can actually be an important tool in the latter category.