"In the view of most urbanists, walkability is a measure of how healthy a city is. It essentially describes how safe and how well-planned a city is for pedestrians, which will in turn determine how often citizens interact with their city."
"There are so many factors that go in to making a city walkable. The factor that I find to be the most important, in pretty much all cases, is how safe the walkways are in terms of traffic. Traffic calming methods become incredibly important when improving an urban space."
Rob Dalton goes on to talk about how efficient various forms of traffic calming turn out to be.