Did some maps set traps?

When the Map Room at the Los Angeles Central Library was gifted with thousands of maps, the collection included every Thomas Guide issued, and some of them had a surprise in their pages: trap streets.

These fictional or misdrawn streets are thought to have been deliberately included as a way to help spot copying. Some were genuine mistakes or just cartographic jokes, but often they were erroneously reprinted for years before being removed — or not.

Map collector/expert CJ Moon, 29, a volunteer with the library's map collection, has found several San Diego roads that never existed but listed nonetheless in Thomas Guides from the early 1980s to early 1990s.

In the 1969 edition, he also found several planned prototype roads (and a golf course) in the San Fernando Valley neighborhood of Porter Ranch. They were gone by 1977, then back in 1987.

Several editions of the map in the late 1990s had a nonexistent road connecting Scadlock Lane and Mulholland Drive in Sherman Oaks, said Glen Creason, the Central Library's map librarian.

And there were many other examples of mystery streets, towns and even islands across the world. Even London A-Z was said to have close to 100 incorrect or fake streets up until at least 2006.

Rand McNally, current owners of the Thomas Guide, says trap streets never existed. But in a March 1981 article in the Los Angeles Times, Barry Elias, then vice president of Thomas Brothers, notes that fictitious names are sprinkled throughout the guides.

Reaching for a San Bernardino edition, he pointed out La Taza Drive in Upland and Loma Drive; both were around in maps into the 1990s but gone by 2005.