The next time you pound the pavement, keep your eyes on the ground. You'll notice the curious spray-painted markings, leaping lines, arrows, crosses, swooshes, and strange acronyms that make up a form of street graffiti that's actually on the street. What do these weird tags mean?
The runes augur the arrival of jackhammers and backhoes. A few days before any urban dig starts, an excavator marks up the designated area, usually in white, and alerts the local underground notification service center. The center puts out a call to the telcos, electric companies, waterworks, and cable outfits that subscribe to the service. The firms respond by dispatching workers with spray cans to map buried infrastructure.
If you know the lingo, you can visualize the dense architecture that sprawls beneath our streets. The paint colors are fairly standard: Red denotes power lines; yellow flags oil and gas; blue is for fresh water; green indicates sewage; purple highlights reclaimed H2O; and orange tags communications or cable TV lines. Some acronyms, like MCI or SBC, are obvious; others aren't. IP, for example, means "iron pipe," and USA stands for "underground service alert" (the aforementioned area slated for excavation). As Mike Hart, a plumber for the San Francisco water department puts it, "I tell my kids that I'm a graffiti professional."
- Erik Davis
credit Erik Davis
What the tags mean: 1) SBC Communications line; 2) municipal transit pole; 3) no Pacific Gas & Electric lines below; 4) 8-inch water main; 5) plastic high-pressure gas line; 6) water line; 7) no phone lines below; 8) telephone vault and lateral lines; 9) electric lines
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Urban Markup Language
