Would it be faster to walk or wait for the bus? Chart and iPhone app tries to work it out for you

If a bus is arriving in 15 minutes and my destination is one mile away, will I arrive sooner if I walk or if I wait for the bus?

This word problem is a real world conundrum for bus riders which Dana Boyd and Chris Mueller tried to answer. Their chart and iPhone app, Walk or Bus, on VisualMotive.com shows whether is would be faster to wait for a bus or walk to a destination.

They assume that buses travel at an average of 15 miles per hour and that walkers can travel at 3 to 4 miles per hour (20 minute to 15 minute miles).