Yesterday there was a horrific crash. When I came back today, there was another. Both involved teenagers on bicycles. In each case, the fire department, police, and eyewitnesses will work together to assign blame. Who made the last mistake that could have prevented this? But that focuses on the wrong issue. It looks only at the active error, the final mistake. Real solutions come from looking upstream, at what are called latent errors. The goal is not to assign blame, but to reduce how often we ever need to. #carculture #crash #pedestriansafety #trafficsafety #urbanism