Markets expand faster when everyone agrees what time it is.

On March 19, 1918, Congress passed the Standard Time Act, formally establishing U.S. time zones and introducing Daylight Saving Time during World War I. The law turned what had been a railroad coordination solution into a piece of federal infrastructure.

Before standardized time, towns set their clocks by the sun. That worked locally, but railroads moving passengers and freight across long distances needed a consistent system to avoid scheduling chaos. By the late 1800s, the rail industry had already divided the country into standardized time zones to keep trains moving safely and predictably.

Congress eventually codified the system and added daylight saving as a wartime energy measure. The decision created a national time framework that still organizes transportation schedules, financial markets, broadcast networks, and everyday business operations.

Once coordination systems like time zones become embedded in commerce, they stop feeling like policy and start functioning like infrastructure.

From bsnsHistory, the daily podcast about the moments when business quietly reshaped the world.

Written and hosted by Ron Trucks. Research and editing by Rodney Russ. Sound design by Angela Cahoy. Music by Cody Martin and Soundstripe.

For more daily business stories, visit www.bsnsDAILYpodcasts.com