That happened many years ago in my neighborhood and it wound up being something to do with future sewer pipe work.

It's some sort of utility marking. They do that every year right before hurricane season around here, so they can find the underground cables if they need to. I've noticed a lot of them lately. They also do it when they're going to put in sidewalks, widen roads, or dig something up so they know where the underground utilities are.

Too crazy... get ready for more than you wanted to know...

Smithsonian: Decoding The City: The Road Graffiti Placed by Utility Workers

Lifehacker: What Those Spray Paint Marks on the Street Actually Mean

The short answer: yellow = gas - oil - steam

Thanks for the free edumacation! :)

Carol in Jacksonville

I think someone musta used the wrong color then cause we have no gas, oil or steam running in our neighborhood. The smithsonian link would not open for me.

the water company uses blue marks in the road to help the meter readers find the meters and i think the telephone company uses orange, electric and cable is above ground and the neighborhood is on septic not sewers. So i sill don't know what the yellow is.

Could there be old gas lines under there that you don't know about? Maybe they're going to remove them? I'd call my utility company and find out what's going on.