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Why do modern cars have dashboards which include useless indicators for the typical driver, such as the temperature of water, pressure of oil and similar technical data?

I would expect that important data would appear when needed (too high of a temperature, or dangerously trending for instance. I do not know whether a 90°C temperature is good, bad or dangerous).

I imagine that regulations enforce one indicator: the speed. It would be ideal if I could place it where it is best for me and then enrich the dashboard with indicators which are relevant to me (not necessarily for others).

Is such frozen design due to

  • tradition? (in the sense that someone designed the dashboard in 1950 and it stayed like this)
  • regulations? (I doubt so, since my last car does not have oil pressure anymore but for some reason the water temperature is still there)
  • customer requirements? (people are maybe attached to knowing the oil pressure)

I looked though the dashboard photos in Google Images and most of them carry the typical large indicators for speed and tachometer and some smaller ones for fuel, pressure, etc. There are very few which are different and they are definitely the exceptions.

closed as primarily opinion-based by tlhIngan, DucatiKiller, MooseLucifer, Pᴀᴜʟsᴛᴇʀ2, Jason C Jul 20 '16 at 4:25

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

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    Because of when people go to the car dealership, sit down in a car and say "Where is the temperature gauge?" then walk out. We had "idiot lights" take over for gauges long ago, and they are not useful. Temp and oil pressure are exactly as important to the car as your temp and blood pressure are to you. You might not understand their value, but that doesn't make the gauge valueless. Many automatic transmission cars have a tachometer. Why? Well, it can be helpful sometimes. You pay a lot for a car (even a used one), an extra gauge or two does not add much to that. – user15009 Jul 19 '16 at 17:49
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    I watch the temperature gauge to avoid going wide open throttle when my engine temperature is below 160 deg F. – Netduke Jul 19 '16 at 17:50
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    @nocomprende: the temperature gauge is as useful for a non-specialized driver as the CPU queue length for someone who browses internet as a simple computer user. This queue is very important, just useless to be known by a standard user. You never have this indication on a computer for a good reason. – WoJ Jul 19 '16 at 17:53
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    @WoJ until something goes wrong. No one was ever placed in a dangerous roadside situation because their browser queue length went too high. Not so for engine temp. What is at risk, and what does the gauge cost? Also, what is the alternative? Provide a special pack of gauges only for people who want them? Many would. It would not save anything. – user15009 Jul 19 '16 at 17:53
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    Just because you do not understand what the gauges mean do not mean they are less useful. Performance cars feature more gauges so you have a better chance of knowing how your engine is operating/how hard you can push it. I know that if i floor my daily driver on a cold engine, the oil might be too viscous to provide adequate protection, so i wait until the engine is good and warm. – Trotski94 Jul 20 '16 at 15:17
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Actually you are saying opposite things. Older cars had more indicators, newer cars rely on ECU. Here's example (my cars):


Opel Manta 1981 dashenter image description here

And my current car Peugeot 107 dashenter image description here

I prefer as many as possible, I want to know everything. But today you don't have to know how to fill the screen wash liquid to pass a theory and driving test. Cars are built for different needs, different people.


And here is my dashboard when I test the engines..enter image description here

Sometimes we see a new topic where people are concerned about driving at 70 MPH at 3rd gear... If she had Tachometer, she probably would notice that. Sometimes in a busy traffic your cooling might fail and start to go over 100 degree C..


I believe some day we will have a big touch screen on a dash and you'll be able to download an app with a different sensor and gauge setup. Surely they are thinking of it already :)

  • Yes. As I commented, too few gauges and experienced people will not buy the car. Inexperienced ones do not run away in terror when they see a couple extra gauges. So, it's a win / don't care. Another factor is that cars seem to be maddeningly far away from service shops and test stands most of the time, but a couple gauges let one diagnose and prevent a lot of problems, on those occasions when the car is on the road. – user15009 Jul 19 '16 at 18:12
  • I had a idle problem on my Peugeot not a long after purchase. And just because I don't have a Tachometer, had to trust my right ear to adjust it. – Arturs Bolsunovskis Jul 19 '16 at 18:16
  • @ArtursBolsunovskis *I; believe some day we will have a big touch screen on a dash and you'll be able to download an app with a different sensor and gauge setup." 1. Buy a cheap OBD2 bluetooth/wifi adapter. 2. Get an iPad or Android tablet, install Torque or a similar app. 3. Duct tape it to your dashboard and enjoy the future! – Jason C Jul 20 '16 at 4:32
  • Btw: The Tesla model S pretty much nails the touchscreen, also has app controls on the steering wheel. – Jason C Jul 20 '16 at 4:42
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They are so "uniformized" and include less-useful indicators because your interpretation of them being less-useful is incorrect.

Unless you're driving the absolute latest development of a passenger car, a completely electric car like a Tesla, then these uniformized indicators are exactly what you want to have.

In a piston engined car, as a driver you should want to know exactly the information provided to you by these "uniformized " gauges.

You want to know:

  • coolant temperature
  • oil pressure (or, in case of a more modern car, just be told when oil pressure is not satisfactory, which is what you now get.. No gauge, but indication if there is low oil level or even worse, no oil pressure in the DIS (driver info. Display)
  • fuel level
  • speed
  • engine RPM

The above are the critical points to know for a piston engined car.

More information would be:

  • fuel consumption
  • range
  • time since departure

as are more typical with modern cars fitted with trip computers.

Your question seems to suggest that information provided to you should require less knowledge about the critical items of the vehicle. This in my opinion is like expecting a pilot to fly a plane but not understand the principles of flight that keep an aircraft in the sky.

As a driver of any vehicle you should understand the basics of the vehicle you are driving and there is no excuse for ignorance.

Basically, for a typical piston engined car:

  • engine should have sufficient oil level and pressure to lubricate working components.
  • coolant should be in operating range
  • tyres should not be worn and have correct air pressure
  • fuel quantity adequate for intended trip

Just to name the basics.

Gauges are there to present the facts. It is always up to the driver to interpret their meaning and to react accordingly.

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    "As a driver of any vehicle you should understand the basics of the vehicle you are driving and there is no excuse for ignorance.". I know how to drive safely, not how to build a car or understand how it works. I expect the person who designed a car did it right (and other checked after that) and will warn me when there is a problem. Not inform me that pressure is 17.3 bars - which means exactly nothing to me. Why should a driver - a user of a utility device - understand the internals of a car when this has zero impact on the safety? – WoJ Jul 19 '16 at 19:32
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    As for the indicators you mentioned, I do not want to know the value, just whether it is OK or not (actually - only when it is not). I can understand that some people are interested in the values (like I am interested in computer internals my wife does not care about) but it does not make them interesting / valuable to the typical driver – WoJ Jul 19 '16 at 19:35
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    Well I disagree. As a driver you are expected to know some of the "internals" to know if it safe to drive.. If you expect a car to do all the thinking for you, then you already have your answer.. The instruments are traditionally simple mechanical gauges. Oil pressure is simply a reading of the actual oil pressure, sent from the engine. If you only want it to show you when something is wrong, then you need electronics to process the information and that adds a layer of complexity there that hasn't been there traditionally. – Steve Oakes Jul 19 '16 at 19:52
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I understand the question, in principle. Not long off will be the day when the desired data will be selected by the user/driver and electronically displayed. Most gauges do indicate an unacceptable value with a red band on the dial at the low or high end of the range, which satisfies your need to just know when conditions are not acceptable.

I propose that the common round gauge shape is related to human conditioning for what "looks right", and the continued presence of temp, oil pressure, volts, etc. is because those are critical variables that many drivers are indeed cognizant of and they would be less likely to purchase the vehicle if they were not there.

Traditionally gauges were round for several reasons. Real pressure gauges use a Bourdon Tube, which is a round-coiled tube with an indicator needle attached to it that expands (uncoils) as pressure from the fluid inside increases. As the tube coils and uncoils the needle moves, giving you a reading. Similarly, traditional temperature gauges often use a coiled bimetallic element which coils and uncoils predictably with temperature changes due to different expansion rates of the dissimilar metals. So "round" was the most economical shape (less wasted space) for a gauge.

Many of the gauges in use today do not truly represent actual values, they are an electronic interpretation. Or even blatantly fake, like my Ford oil pressure "gauge" which looks like a gauge but is actually just a graphical representation of a signal that is either ON or OFF according to a pressure switch sender. It could just as easily be an "idiot light" that only informs me when the value is out of range.

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