Caltrans is proposing to spend $1.8 million to install a giant underground “floating slab”—coupled with a “geo-synthetic drain” to fix the chronic water seepage that’s afflicted the Castillo Street underpass since the day it was built in 1961. Caltrans last tried to fix the problem in 2015, spending $800,000 to install street pavers that were supposed to carry seeping water but which by any reckoning have made the problem worse. The water accumulating in the pavers—the underpass dips into the city’s water table—served to make road conditions slippery. As the space between pavers has expanded in the presence of water, cyclists have increasingly gotten their tires wedged and stuck. As a result, the number of collisions and falls has doubled in the past two years. City traffic planners, like Peter Brown, insist the water problems are sufficiently serious that a major reboot of the Castillo Street inter change is required. According to estimates now several years old, that would cost $21 million. The work now proposed will cost $1.8 million, but where that money will come from remains very much unresolved. In the meantime, Caltrans is not allowing cyclists to ride down that underpass, instructing them to get off and walk their bikes through the interchange. City traffic planners are hoping construction can take place this summer when classes at City College are lightest.