During the latter half of the 20th century, traffic engineering was based on the principles of “forgiving design“. Under this approach, streets were widened and curbside features were removed in the name of safety and flow. But this didn’t work, and as Better Cities & Towns writes, not only did it never work, it was based on conjecture. By 2005, at least 10 studies had found that this design made streets less safe, yet no policy changes had been made. There is hope however. A data-driven approach shows that narrower streets, bordered by previously banned features, like trees, can reduce crashes while also creating more people-friendly environments. The wide streets can also become part of the solution, with excess space devoted to bus and bike lanes, as well as pedestrian safety features like bulb outs. The redesign of thousands of streets requires skill and care, this is a major opportunity for traffic engineering to become leading supporters of the livable city.