We’ve created a monster. For a century, traffic engineers and car companies have designed roads and vehicles to enable speed while expecting people to have the self-control to slow down. We post little black and white signs telling people to drive below a certain “speed limit,” which, predictably, drivers ignore. Nationally, because of these design decisions, traffic violence is the leading cause of death for children and adolescents. People of color suffer the most: Black pedestrians are hit and killed by motorists at twice the rate of white pedestrians. Speed is a problem here in Berkeley, where a third of all severe and fatal collisions are caused by drivers traveling at unsafe speed or failing to yield at crosswalks.