Caltrans tests the underground steel and concrete supports piles that support bridges and other freeway structures to ensure against defects. In numerous cases, a Caltrans technician either falsified test results or failed to verify the accuracy of his gauge. Some experts believe that in the event of an extreme event such as a powerful earthquake, the strength of some of the structures below might be in doubt. Other structures for which data were discarded or are otherwise unavailable might also be affected. Caltrans said all the structures are safe.
Use this interactive map to view these structures more closely. The precise location of the bridges, ramps and and signs are not always available from Caltrans documents, so these locations are approximate. In some cases, the structures were built too recently to be visible in aerial imagery.
Map by Nathaniel Levine firstname.lastname@example.org
Sources: Caltrans, Bee reporting