Matt @ 37Signals discusses new countdowns being used at pedestrian crossings (crosswalks). Did you ever count how many redundant messages are available at a pedestrian crossing? Good, let’s be sad together and count them, then. At a workshop one time, various attendees from different countries came up with a list of cues, something like the six below:

• The walking man (is there a walking woman anywhere in the world?) or “Walk”/”Don’t Walk” message.
• The main traffic lights for drivers.
• Countdown displays.
• Display next to the button, indicating if it’s already been pushed (in which case, currently in “Don’t Walk” mode).
• Sound. (A continuous noise to indicate whichever phase they’re in, and/or a transition sound.)
• Cars and pedestrians. (Not actually designed and not reliable, but certainly an indication.)

The redundancy is presumably to cope with different sets of disabilities, as well as improve safety for everyone. Software developers don’t always like redundancy - it goes against just about every fundamental design principle you care to name - but users generally benefit from it. So it’s a matter of architecting things so that redundant UI doesn’t lead to redundant code. e.g. point two event handlers to the same Command object.

Yeah, another funny thing about crossings is the button. In one place (Singapore?), I was told not to push it, because it’s only for disabled or elderly people (and of course, ignorant tourists). Everyone else just waits and it will turn green eventually.