http://phillymotu.wordpress.com/2013/01 ... -activity/
A key component to achieving these goals is Complete Streets’ ability to lower the overall speed of traffic, which in turn increases roadway capacity. This means that even though cars are moving slower, more vehicles can pass through an area. Although this might seem counter intuitive, when vehicles are traveling at slower speeds, they also travel with less distance between each other, allowing for a greater total traffic. In fact, the report shows that lowering vehicle speeds from 40mph to 25mph will increase total vehicles by approximately 400 vehicles per hour.