When Traffic Lights Make Us Stop and Think

A manhole cover in Chapel Hill, N.C., with blue arrows painted on its corners.

Like traffic lights, manhole covers (including this one in Chapel Hill, N.C.) have their own secrets. To learn what the arrows have to tell us, explore the photo gallery.

Brian Hayes

Send Us a Photo

At our Flickr site, add your pictures of things you see that you want to know more about.

Have you got a head-scratcher to share with "Science Out of the Box?"

For the past 15 years, writer Brian Hayes has made a hobby out of studying — and photographing — the manmade. He is the author of Infrastructure: A Field Guide to the Industrial Landscape.

Inspired by his daughter's questions, he set out to learn more about the workings of power lines, fire hydrants and other mysteries of the industrial age.

His subject on a recent field trip to the traffic command center in the nation's capital: How do stoplights work?

Books Featured In This Story

Infrastructure
Infrastructure

A Field Guide To The Industrial Landscape

by Brian Hayes

Hardcover, 536 pages | purchase

close

Purchase Featured Books

  • Infrastructure
  • A Field Guide To The Industrial Landscape
  • Brian Hayes

Comments

 

Please keep your community civil. All comments must follow the NPR.org Community rules and terms of use, and will be moderated prior to posting. NPR reserves the right to use the comments we receive, in whole or in part, and to use the commenter's name and location, in any medium. See also the Terms of Use, Privacy Policy and Community FAQ.