Thanks to commenter Stephen for prodding us to post on the new report from the Rails-to-Trails Conservancy, "Active Transportation for America" (download the PDF here).

What
makes the report notable are the numbers it contains. It’s jam-packed
with quantifiable benefits that would result from increased investment
in infrastructure that encourages and supports pedestrians and
cyclists.

For instance, the report’s authors write:

• Increasing
  the bicycle and pedestrian share of trips of one mile or less from
  currently 31 percent to 40 percent under a Modest Scenario, and to 70
  percent under a Substantial scenario, would result in 28 billion or 49
  billion miles driven avoided, respectively.
• Modest
  increases in bicycling and walking for short trips could provide enough
  exercise for 50 million inactive Americans to meet recommended activity
  levels, erasing a sizeable chunk of America’s activity deficit.
• For
  the price of a single mile of a four-lane urban highway, approximately
  $50 million, hundreds of miles of bicycle and pedestrian infrastructure
  can be built, an investment that could complete an entire network of
  active transportation facilities for a mid-sized city.
• The
  financial value of improved mobility, fuel savings, greenhouse gas
  reductions, and health care savings amounts to more than $10 billion
  annually under our Modest Scenario. For the Substantial Scenario,
  benefits would add up to more than $65 billion every year. These
  benefits dwarf historic spending for bicycling and walking, which was
  $453 million per year for 2005–2007 under SAFETEA-LU, and a mere $4.5
  billion cumulative federal investment in these modes since 1992, when
  bicycling and walking first received documentable federal funding.