## Thursday, August 28, 2014

### How Long Would It Take to Walk Every Street and Avenue of New York City?

What If has some estimates, as it answers the question, Can a person walk all the streets of New York City in a lifetime?
Most people wouldn't have trouble walking 10 kilometers (6 miles) in a day. If the city were covered in kilometer-long streets laid down edge-to-edge, with no space between them, you could fit a thousand roads side-by-side in 10 kilometers. That means a person could walk back and forth across an entire 10km by 10km grid in, at most, 3 years.

Winning Snake strategy, if you're really fast and extremely patient.

I don't know how many 10 km square swatches it takes to cover New York City, but it's probably not very many.

And since NYC has some space not occupied by streets, this tells us that the answer to the first part of Asaf's question is almost certainly "yes"—purely from a geometry standpoint.

Here's another approach: I happen to remember that the US Postal Service employs about half a million people. NYC's population is almost 10 million people,[5] so almost 1 out of every 35 Americans lives there.

If New York also has 1 out of every 35 postal employees, that's about 15,000 people...

If all those employees were letter carriers, and they visit every address in the city every workday, that would mean it takes a total 15,000 x 8 hours = 14 person-years to traverse the city—much less than a lifetime! Since lots of postal employees are not letter carriers, and real letter carriers stop frequently, this estimate is probably still much higher than the reality.

(ht Tim Harford)