By Mike DeNardo

PHILADELPHIA (CBS) — They’re not new, but to many they’re still a mystery. What are those waffle-like yellow grids nailed to local utility poles?

“I agree that it looks like a grid,” said one motorist.  “A reflective grid, to notify someone of something.”

It’s a reflector, so that drivers won’t crash into poles and cause power outages, according to PECO spokeswoman Cathy Engel Menendez.

“It has the ability to work with a lot of different angles by that waffle design,” Menendez says. “And really, what we’re hoping, is that it will be much more effective at attracting drivers’ attention to the utility poles.”

Since 2007, PECO has been installing the reflective grids as poles are inspected, every ten years.

About half of PECO’s 400,000 poles have them so far.