The more kids get driven to school instead of walking, the more chaotic the drop-offs and pick-ups become. Greater Greater Washington's Matthew Kohler notes that the rise of school choice policies adds a whole new wrinkle, as students shift from neighborhood schools within walking distance to schools farther away.
Most places in the U.S. still use 20th century metrics to measure the performance of transportation systems. The emphasis is still on moving cars, not improving transit service or reducing traffic injuries. One of the exceptions is DC, where the DOT is letting people assess streets according to a different set of priorities.