Why are so many street name typos stamped into San Francisco sidewalks?

Whether you’ve lived in San Francisco all your life or simply stopped by for a visit, at some point you might be waiting at an intersection when you notice the street name paved on the sidewalk. That might seem like overkill but it’s all part of the city’s plan.

Photo by ThRogers / CC BY-NC-ND

The city wants you to know where you are at all times, so every time a San Francisco sidewalk gets paved or re-paved, hired contractors from the Department of Public Works stamp the intersecting street names onto the concrete before it dries. The metal letter stamps get arranged side by side, and then they’re flipped over, engraving the street names to help lost San Franciscans find their way home for years afterwards.

However, the whole act of arranging the letter stamps and then quickly flipping them doesn’t always go according to plan. In fact, if you walk around the city with your eyes open, you might notice several misspellings, and even some backward letters, on the streets of San Francisco. Some of the errors are cringe-worthy while others are just downright hilarious. Some people have found it so amusing to hunt for these typos that communal groups dedicated to the subject have popped up on Flickr.

Street stamp enthusiast Thomas Rogers told SF Gate that he first discovered a misspelling at the intersection of Missouri and Mariposa Street in Potrero Hill. Missouri was spelled M1SSOR1. The “i” letters were substituted with 1s, the U was utterly forgotten, and the M was actually an upside-down W. Since then, Rogers has collected more than 150 typos, which he documents in his own Flickr album.

Rogers isn’t alone in finding numerous typos around the city. Frances Hochschild told SF Gate that she found “BRODWAY” and “BROADWEY” at the same intersection — Broadway and Divisadero Street in Pacific Heights. The Department of Public Works has since fixed these twin typos since a contract job on that particular sidewalk happened to be ongoing at the time. As for older typos? They aren’t likely to see corrections anytime soon unless the entire curb happens to need a redo. 

Photo by throgers / CC BY-NC-ND

If you live in a different city and this story has encouraged you to hunt for street name typos in your own hometown, you may be out of luck. Street name stamps like the ones seen in San Francisco are rare outside of the City by the Bay. Most cities opt for construction stamps featuring the contractors’ name and construction year to be placed on new sidewalks, but this is done simply for quality assurance.

As for how this unique custom of engraving street names first started, some theorists believe the tradition began after the devastating 1906 earthquake that destroyed much of the city and made it difficult for resident to recognize where they were. However, the original ordinance that started the practice was actually placed into effect on Nov. 6, 1905.

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