Next time you’re cruising on the interstate, take some time to spot all the different highway shields. Are there single digits? Double? Triple, even? What do the odd and even numbers actually mean?

The story of America’s interstates is usually told as a straightforward tale of postwar progress, but the real origins are stranger and more contested than the green signs suggest. The Dwight D.

Since the Interstate highway system was created from whole cloth, rather than emerging through the years, it shouldn’t come as a surprise that there is a defined logic to the numbering system that ...

There were roads across the United States before 1926, but they weren’t systematically named, numbered or otherwise organized. Instead, the country was crisscrossed by a series of loosely connected ...

HAVERHILL — If you've traveled Interstates 93 or 495 in the Merrimack Valley recently, you may have noticed that exit numbers are not what they used to be. The state is engaged in making a change from ...