Contractors place white markings down where they plan to dig and then dial 811. This dispatches a request to send out specialists called “utility locators” who bring tailored equipment like ground penetrating radar to trace underground lines. They then use specific paint in standardized colors to indicate what they find and use special symbols and patterns to communicate back to the builders.
White – proposed excavation routes
Red (PMS 1795) – power and lighting cables
Orange (PMS 144) – communications, signal lines
Yellow (PMS 108) – gas and oil
Blue (PMS 285) – potable water
Green (PMS 3415) – sewer and drainage lines
Purple (PMS 253) – reclaimed water and irrigation
Pink (PMS 219) – temporary survey markings
A special, fluorescent marking paint is used that is high visibility and designed to be sprayed straight down and stick to dirty asphalt. It also fades away after a few months (as you will notice from several of the images). Builders can then use the marks to dig without hitting live utilities or lines. There is also an established syntax for placing markings provided by the Common Ground Alliance. Quite fascinating to learn about this (somewhat) quiet conversation happening between thousands of independent entities everyday right under our feet.
There are pics in few categories I’m a little short on, but I’ll remedy that on a future walk.
So how does this track to what we do? In digital spaces, our initial plans are like the white markings. Tools like design audits and accessibility reviews then can be used to give teams the clarity they need to keep building (the high visibility color codes). This helps spot and address potential hazards early—so users can navigate our products with confidence and ease.
If this hits home and you’d like help with your own design system or audit, drop us a line—we’d be happy to set up a time to talk.
