By Angie Schmitt, October 31, 2014
Places with less traffic have more congestion. Graphic: City Clock
Here’s a great visualization of what cities get out of the billions
of dollars spent on highways and road expansion: more traffic.
Justin Swan at City Clock made
this chart showing the relationship between congestion levels, as
measured by TomTom, and car use. (Yes, it has no X axis — here’s Swan’s explanation
of how to read his chart.) The pattern that emerges is that the places
with the most traffic and driving also have the least congestion.
We know from the work of Joe Cortright that
the traditional definition of congestion is a poor way to measure
people’s ability to get around their city – because it doesn’t reflect
the actual time people spend traveling. Drivers in Dallas and Houston
may stew in gridlock less than people in other cities, but they spend
more time on the road.
Swan notes that the most congested places are also the places where
people have good travel options that don’t involve driving. His chart
suggests that car congestion itself is not the problem that needs to be
solved — as long as there are other ways to get around, in a congested
city few people will actually have to sit in traffic.