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Why Do Drive-Up ATM Machines Have Braille Dots?

ATM machine; via iStockphoto.com

Robert Frank: As promised yesterday, today’s economic naturalist question is one of my two all-time favorites from among the many thousands submitted over the years by former students.

“Why,” Bill Tjoa wanted to know, “do the keypad buttons on drive-up cash machines have Braille dots on them?”

It’s an interesting question, since the patrons of these machines are almost always drivers, none of whom are blind. The answer, according to Mr. Tjoa, is that because ATM producers make keypads with Braille dots for their walk-up machines anyway, it is cheaper just to make all machines the same way. The alternative, after all, would be to hold two separate inventories and make sure that each machine went to the right destination. If the Braille dots caused trouble for sighted users, the extra expense might be justified. But they do not.

Shortly after Ben Bernanke and I described this example in our introductory economics textbook, I received an email from a professor saying that Mr. Tjoa’s answer was wrong — that the real reason for the Braille dots is that they are required by the Americans With Disabilities Act. He sent me a link to an ADA web page that described the regulation. To be sure, having Braille dots on drive-up machines might be useful on occasion, as when a blind person visits a drive-up machine in a taxi and does not want to reveal his PIN to the driver.

I thanked my correspondent but also urged him to consider the possibility that Mr. Tjoa’s argument might help explain why the regulation requiring Braille dots was adopted. Had it been costly to require Braille dots on the drive-up machines, my guess is that the rule would never have been enacted. But putting dots on the drive-up machines was costless. And since the dots cause no harm and might occasionally be of use, why not require them? Doing so would enable regulators to claim, at year’s end, that they’d done something useful.

Tomorrow I’ll post the other member of the pair of my all-time favorite questions submitted by former students: “Why do brides spend thousands of dollars on wedding dresses they’ll never wear again, while grooms, who will have many future opportunities to wear a tuxedo, usually end up renting a cheap one?”

Robert Frank’s latest book, The Economic Naturalist’s Field Guide: Common Sense Principles for Troubled Times, was published last month. He is guest-blogging for the Business Desk for the next few weeks.

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