Next-gen digital speedometer versus 1939 safety speedometer

Now, this is cool. A few weeks ago, I discussed how a digital instrument cluster can provide visual cues to help drivers avoid speeding. For instance:

Well, guess what. Engineers for Chryler's now-defunct Plymouth division came up with this concept years ago — in 1939, to be exact. That's the year Plymouth introduced its "safety speedometer" in the P8 model line.

From what I've read, these speedometers switch from green to amber to red, depending on the car's speed. I've only seen still photos of these speedometers, but allow me to invoke the magic of PhotoShop and reconstruct how I think they work.

The safety speedometer has a rotating bezel. Embedded in this bezel is a small glass bulb. At speeds from 0 to 30 mph, the bulb glows green:

At speeds from 30 to 50 mph, the bulb turns amber:

And at over 60 mph, the bulb turns red:

Of course, given the limitations of 1939 technology, the Plymouth safety speedometer can't take driving conditions or the current speed limit into account. The speedometer glows amber at 30 mph, regardless of whether you're driving down a quiet neighborhood or on a busy highway.

Compare this to a software-controlled digital speedometer, which can take input from multiple sources, both within and outside the car, to provide feedback that dynamically changes with driving conditions. For instance, a digital speedometer can acquire the current speed limit from a navigation database and change its display accordingly.

Also, a digital speedometer can intelligently deemphasize unnecessary information to reduce driver distraction. For instance, it can dim any gauge that is displaying values in the normal operating range. Like so:

Mind you, I'm just scratching the surface of what a digital instrument cluster can do. Check out Andy Gryc's new whitepaper to get a better idea of how automakers can implement — and benefit from — this technology.

p.s. I can't locate the website that contains the original, pre-PhotoShopped photo of the safety speedometer depicted in this blog post. If you recognize the photo and it's yours, let me know, and I'll give you the photo credit and link to your page.


Bill said...

I can see the need for this back then, those bald radial ply tires would explode if you went any faster, not to mention the all round drum brakes!

Nowadays, you need a marker for "chance of fine", "heavy fine", "license suspension", "jail" :-)

Paul N. Leroux said...

Yes, people forget that, in those days, tires blew often.

I like your suggestion re chance of fine, etc. Maybe the cluster could plug into a location-based service and display legal penalties for the town, county, state, province, etc. you are currently driving through! :-)

Anonymous said...

The PDF whitepaper link doesn't work...

Paul N. Leroux said...

Thanks for notifying me of the bad link, Anonymous! I think it should work now.

- Paul

Anonymous said...

Hello, the whole idea is cool/unusual, but in practice I would prefer traditional speedometer. Even more, I wouldn`t like for the speedometers like this to become common. Here`s why :

1) Reliebility reason. Speedometer should just work, year-by-year, during the life of the car. Digital speedometer like this has much more points of failure.

2) Psychological/driver responsibility reason.
At first, 'visual cues' will not work reliebly - I`m very doubt that there will be a database containing speed limits for all roads. (Also, it should be updated frequently)

Second, and the most important - driver responsibility. Driver MUST be careful on the road, he MUST adjust car speed according to the spid limits and (!) driving condtitions.

What you are telling about is cool technlology that may *sometimes* work. May the driver to sue BMW in case of there was a mistake in the speed limit database and he temporarily lost his driver license
because he followed 'visual cues' ? Of course, not, because this feature will be delivered with no guarantees.

Experienced drivers will not use such a feature anyway and rely on what they see on the road, but it may be the source of confusion/problems for the young drivers.

Sorry for my imperfect English.
Generally, your blog is very interesting and I enjoy reading it.


Paul N. Leroux said...

Good points, Konstantin. Admittedly, the idea of displaying visual cues based on a navigation database may or may not fly. The idea does suggest, however, that digital clusters allow automakers to introduce some interesting features, provided those features don't compromise safety or reliability. My guess is that digital clusters will become more and more popuar, partially because automakers need a way to integrate the increasing amount of information coming from tire pressure warnings, Internet connections, roadside information systems, etc, etc, etc. A digital cluster allows the driver to see only the subset of information he/she needs at any particular time.

That said, you're absolutely right: automakers need to address reliability and longetivity issues. And, yes, drivers must be held responsible for their driving behavior. That's why I agree that in-car systems can provide only so many visual cues; we can't lull drivers into thinking that the car will always tell them if something is "wrong."