How do you learn from a really big mistake?
Walk across it.
Which is why I recently found myself putting on a windbreaker and beginning a long, slow walk across the east span of the Bay Bridge, from Oakland to Yerba Buena Island. This piece of the bridge, completed in 2013, is probably the biggest California mistake of the last generation. The east span was completed a decade late, cost seven times more than official projections, and remains dogged by serious safety concerns.
However, the bridge does have one virtue: It holds lessons …