December 1, 2020

Archives for October 2003

Remote Controls for Traffic Lights

Many cities have installed systems that let emergency vehicles control traffic lights via infrared remote controls, thereby getting to the scene of an emergency more quickly. This is good.

Yesterday’s Detroit News, in a story by Jodi Upton, reports on the availability of remote controls that allow ordinary citizens to control the same traffic lights. Now traffic engineers worry that selfish people will use the remotes to disrupt the flow of traffic.

As Eric Rescorla notes, this could have been avoided by using cryptography in the design of the original system. Instead, we’re likely to see a crackdown on the distribution of the remote controls, and the predictable black market in the banned devices.

This seems like a classic example of the harm caused by deploying a technology without considering how it might be abused. It would be interesting to know why this happened. Did the vendor not stop to think about the potential for abuse? Did they think that nobody would ever figure out how to abuse the system? Did they fail to realize that anti-abuse technologies were available? I wish I knew.


As an experiment, and in the hopes of defraying the cost of running this site, I have started sticking ads onto this site’s individual entry pages. The service uses some kind of algorithm, based on the pages’ content, to decide which ads to place on each page.

Please let me know what you think.

Swarthmore Bans Indirect Links

Ernest Miller reports that Swarthmore now is yanking the Net connections of students who linking to a page that links to a page containing the infamous Diebold memos.

So Swarthmore students can’t make a two-hop link to the memos (i.e., a link to a link to the memos). Can they make a three-hop link, say by linking to Ernest Miller’s report? Can they make a four-hop link, say by linking to the page you are reading right now? Can they make a five-hop link, say by linking to my personal home page? Maybe some enterprising Swarthmore student will do an experiment to find out.

UPDATE (1:40 PM, Oct. 27): James Grimmelmann at LawMeme says that Diebold’s own home page contains a five-hop link.