24 hours in the day, so write them that way

An alert reader of yesterday’s post on barely off-airport rental cars noted the use of the 24-hour notation rather than the 12-hour with am/pm common in the US. The Rapid Traveler has found use of 24-hour notation tremendously beneficial to avoid misunderstandings, both internationally, and perhaps surprisingly, in the US.

Internationally, many countries use 24-hour notation, or if not in general use, at least for travel applications such as train tickets. It is a lot easier to mistake 5:00 am for 5:00 pm than 5:00 am for 17:00. And the people familiar with Arabic numerals in the world certainly outnumber those familiar with the English alphabet.

Shanghai - Suzhou

Photo by orangeandmilk

24-hour notation is surprisingly useful in the US as well, precisely because Americans are generally unfamiliar with it and need to pause to process what they are seeing. When The Rapid Traveler’s employer’s EVP, International was flying from Beijing to Atlanta a couple years ago, the company’s travel agent quickly booked a Korean Air itinerary arriving just past midnight in Seoul Incheon, continuing to Atlanta late the next morning. The agent (later interviewed) saw the 12:10 am and 10:30 am on a computer booking screen (a jumble of text much less clear than even the Expedia example shown here), and did not stop long enough to realize that it was 12:10 am not pm, chalking up the rest (incorrectly) to time zones. Fortunately The Rapid Traveler asked the EVP if he was staying in Seoul’s convenient transit hotel when the little matter of needing a hotel for the layover came to light.


If the agent had seen a screen like that from Korean Air’s website, she probably would have immediately been altered to the need for a hotel. It helps that this screen sticks the layover right in between the flights rather than burying it in total flight time at the bottom.


To cover his bases, The Rapid Traveler generally writes times as HH:MM am/pm, as in 18:15 pm for 6:15 pm.

It is amusing speculation to wonder if, in the 2010 dispute between the Civil Aviation Administration of China (CAAC) and American Airlines (AA) over the proposed time slots for its Chicago-Beijing route, where AA apparently did not fully lather up the Chinese authorities, if CAAC might have been able to point to some AA correspondence specifying 2:20 and 4:20 and not including am/pm and not written in 24-hour format. “Well, it says right here you wanted 2:20!” Anyone who has sat on a Chinese runway in a non-Chinese carrier’s plane while Chinese carriers cut in front by the dozen know it is an uphill battle to get decent treatment, and this kind of pettiness is conceivable, though again to stress, totally ungrounded in public fact.

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