There are lots of ways to display actual speed on an automobile dashboard, but none of them, I believe, are more efficient at conveying information than a pointer describing an arc on a round dial: once you've learned the scale, it's not necessary to look at the numbers, only at the relative position of the pointer.

Chevrolet Nova speedometerFor the most part, Chevrolet has followed this design, though this study by graphic designer Christian Annyas, which shows a sample of Chevy speedos from 1941 to 2011, finds several departures from the norm, including one I dealt with personally for a few years: the horizontal dial with a pointer covering an arc somewhere around 120 degrees. (The fact that the speedo's scale reads up to 120, a speed the car probably could not do, is likely pure coincidence.) I never did warm to this design, though: the scale is horribly compressed between 30 and 90, where almost all of my driving occurred, and about the only speed I could tell in a hurry was 60, because the pointer was straight up.

Annyas, for some reason, has skipped over most of the Joan Claybrook period, though there's an '85 Silverado speedo maxing out at 85; I attribute this to They All Look Alike Syndrome. He definitely doesn't like digital readouts:

Some characters of the typeface look very similar to others (for instance 0, 6 and 8), which makes it harder to figure out whether you'll get a speeding ticket or not. Not an ideal situation.

I blame this on the ubiquitous seven-segment display used for almost all such units. (One exception: Honda.)

Chevrolet Monte Carlo speedometerAnd even proper dials can present distractions. Look at the first-generation Monte Carlo. (Annyas offers a shot of a '70 version, basically identical to this, except that he's rendered all his versions in an elegant greyscale for simplicity.) When you're driving, your eye isn't going to be drawn to the scale where the pointer is: it's going to be looking at the middle of the gauge, where the pointer is at its widest — and where there's a Big Round Thing in motion. At the very least, the center section should be the same color as the background, making it, if not exactly invisible, certainly a lot less conspicuous.

Infiniti I30 speedometerFor comparison, here's what I have to look at on a daily basis. The backlighting extends to the scale and to the pointer, but not to the base of the pointer in the center. In practice, unless you get the sun at a particular angle, you can't see the center section at all. The tach, to the right, follows the same pattern, though at 6600 rpm the scale turns red for exactly the reason you'd expect. (This is not actually from my car, but it's the same model and year; I have about 133,000 miles at the moment. Please note that the odometer uses those same seven-segment displays, but the application here is less critical: no one is going to give you a ticket for having too many miles.)

All this may become irrelevant once Google, or whoever, figures out some way to convert all of us drivers into mere passengers, while the machinery does all the work. (Expect a phalanx of lawyers to fight any such plans once the implementation is imminent — and another of similar size, of course, to help push them forward.) And various automakers from time to time — MINI, Saturn, Scion/Toyota — have seen fit to stick the speedo in the middle of the dash for reasons unknown, though I'd bet none of those reasons are "Because it costs more." Still, J. Random Driver, Jr., the first time he clambers into the driver's seat, even if he's six and a half and isn't going to be able to reach the pedals for several years yet, is going to look at this big dial and think "Wow, I can go that fast!" Even if he can't. (He certainly can't in my car, which tops out a hair above 130; then again, he can't even see the numbers if the key isn't in the ignition.) The speedometer is an irreducible part of American car culture, which is undoubtedly why Christian Annyas thought it was worthy of a design study — and definitely why I thought I'd mention it here.

The Vent

#748
  8 November 2011

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