In a car, if you press the accelerator it can do one of three things:

  1. make the car go forward.
  2. make the car go backward.
  3. not move the car at all.

The result depends on what gear the car is in, but in many cars (especially ones with manual transmission), there's little visible indication of what "mode" the car is in.

an image of a stick shift Aside from a slight shift in the position of the interface, there's no visual cue of the car's mode.

Consider this (hopefully hypothetical) situation: a teenager owns a manual transmission car. He drives into the mountains with a group of friends, and stops the car facing a cliff. Later in the day, there's some form of mountaineering accident (or bee sting or bear attack) incapacitating the driver. Under the pressure of the situation, his friend (a relatively inexperienced driver) gets into the driver seat instead. Whenever this friend parks his own car, he puts it in reverse, so without thinking, and without any visual cue, he assumes that this car is also in reverse and accelerates right off the cliff edge.

How could the mode of the car's transmission be made clearer to help prevent this error (without being an annoyance in day-to-day use)?

Assume that the driver wanted a manual transmission because he heard they're cheaper and get better gas mileage, and he likes the increased feeling of control it gives him. (Just saying "make the transmission an automatic" isn't an option for this user base.)

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    Non-issue in the real world. Any driver trained for manual transmission will shift into either the first gear or reverse after starting the car. While driving, you can tell the gear by the car behavior and the position of the stick (without taking your eyes off the road), and downshift/upshift as appropriate.
    – dbkk
    May 9, 2013 at 16:53
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    Shifting should be instinctive by the time a new driver is done with training sets off on the road. Driving should not be a trial-and-error process, nor a "start and figure it out as you go" situation. The driver who does not instinctively know the gear and is looking for a gear indicator while driving (no matter how obvious) is getting distracted from the road and does not belong in a manual-transmission car.
    – dbkk
    May 9, 2013 at 17:15
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    It's an interesting hypothetical, but I think in reality, anyone that drives a stick intuitively and habitually always shifts before accelerating.
    – DA01
    May 9, 2013 at 17:34
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    As for 'always leaving car in one gear' if that is a real issue, then I think it's a valid question, but I don't know of any data that says that's a real issue. Most everyone I know that drive a stick has a habit of putting the vehicle in neutral as they start the vehicle.
    – DA01
    May 9, 2013 at 17:36
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    I already answered, but I sort of misread the question. The hypothetical is interesting, but it's such a fringe situation that maybe natural selection for the careless driver is the best solution :) May 9, 2013 at 18:00

5 Answers 5


A common affordance which informs users about cars reversing in india is the use of audio tunes to inform the user that the car is currently in reverse. Though its a very good affordance which immediately informs the user and the people around him that the car is in reverse, it does suffer from the issue of contributing the noise pollution and also the problem of people selecting really weird car tunes.

An alternative approach would be to show the currently selected gear in the panel as shown below

enter image description here

  • +1 for reverse gear tunes too, but you could also use a different tune for a forward gear. perhaps 2 quick beeps. May 12, 2013 at 23:04

A few solutions could be:

  1. Color coding on shifter - Forward moving gears could be colored green while reverse is left white. Red wouldn't be ideal since that's so closely related to 'stop'. There are problems with this approach because does white clearly mean reverse? Would a user be looking at the gear when choosing them? Could the graphic on the gear selector be rubbed off?
  2. Icon indication on shifter - You could use individual icons for each gear with either an up arrow or down arrow depending on the direction. That would take up double the space since the arrows would probably be as large as the numbers. So, you could group the gears with one arrow for forward or reverse. The downside is using icons on the shifter is they would be obscured while the user was actually driving.
  3. Icon indicator on the dashboard - Up/down arrows on the display cluster would solve the obscuring of the indicators on the gear shifter and also the visual complexity the gear shifter solutions could cause. However, the problem here would be would the user know to look at the dashboard when choosing a gear? That information might be lost to the user when they most need it (learning how to drive) and only become apparent after they've learned how to drive.

This problem reminds me of two things, a quote and a similar situation in airplanes:

Everything should be made as simple as possible, but not simpler.

It's disputed who said that quote, but Einstein is the popular choice. The thought here is that at some point, making something more simple than it already is has the opposite effect. Adding indicators on the shifter or dashboard may make it seem more simple to drive, but in reality it makes it more difficult and isn't able to be a substitute for actual drivers training or a manual.

Airplane Cockpit

The Airplane Cockpit

There's a popular UX story that discusses how you could theoretically make a cockpit "simpler", but that simplicity wouldn't make an airplane easier to fly, in fact it would make it more difficult.

The complex set of gauges and controls is designed for a trained pilot, the pilot who is flying for endless hours during their career. Making the cockpit more simple would only benefit that pilot in the "learning how to fly" process that happens in their first hours and years. Once the system has been learned, simplicity for the new user makes the system more cluttered for the experienced one.

Your example would be aimed at helping the beginning driver, but much like the airplane cockpit, making the controls more simple would benefit a very small minority and confuse the more experienced ones.

Another thing to think about is would your user feel comfortable driving with that new information? Using a manual transmission has a much more difficult challenge for drivers that knowing which gear is for forward or reverse movement: using the clutch. Think about hopping into the simplified cockpit that's absolutely perfect for new, untrained pilots. Would you feel comfortable taking off and flying yourself and your family around? You need a bit of confidence in both of these situations to do them well. Training would be best, but a set of instructions could be a decent substitute.

So, to answer the question, training or a set of instructions are the best ways to get your new driver familiar with the workings of a manual transmission.

  • Up vote because of the last sentence. May 9, 2013 at 16:53
  • +1 for the list of three possible solutions, but I disagree that this won't be an issue for experienced drivers. You'll notice that the reason the driver in my example makes the mistake is that from his own experience driving, he has grown accustomed to expecting the car to be in reverse when it starts, so he doesn't expect the change, and has no feedback to suggest otherwise. May 9, 2013 at 17:00
  • sorry, I should have addressed that part a little better. But, the point is, you're trying to compensate for someone's inexperience/carelessness, which needs a solution that doesn't make the operation of the car more difficult for the experienced user. May 9, 2013 at 17:09

This is not an answer. It is a lengthy comment on the phrasing of the question.

How could the mode of the car's transmission be made clearer to prevent this error?

suggests that the driver is unaware of the mode of the car's transmission and that clearer, more persistent, less ambiguous, more salient, etc., communication of the mode of the car's transmission will prevent driver error.

Moving directly to a 'more information/feedback' solution to this type of error may not be the right answer. I recommend review of the current thinking on human error during system operation.

For example:

  • Anything written by James Reason on human error.
  • David Woods' podcast on human error Note: I have read Woods articles and chapters on errors. I have not listened to the podcasts.
  • Other readers familiar with this topic, please chime in with other suggestions or critiques of these two recommendations.

    More feedback may not useful because errors persist in the presence of

  • extensive feedback already available about the mode of the car's transmission.
  • training drivers receive
  • presence of lock outs to prevent errors like the one described in the question.


  • All cars provide visual and proprioceptive feedback regarding the direction of travel of the car. As the driver releases the clutch, the car starts to move. The driver can feel and see the direction of movement. This rate of feedback increases gradually. In most cars with manual transmissions, releasing the clutch rapidly causes the engine to stall - unless you are performing a burn out.
  • All cars with manual transmissions provide visual and auditory feedback about the appropriateness of the gear for the task. In other words, as the driver releases the clutch, the sound of the engine changes as it enages the clutch. If the gear is too low, the needle on the tachometer approaches the red line and the engine is loud. If the gear is too high, the tachometer needle hovers near the low end the engine sounds entirely different.

    Training While people are trained to put a car with a manual transmission in gear when parking the car, starting the car while it is in gear is not normal. Most people are trained to put the car in neutral before turning the key.

    Lock outs

  • Shift locks are available for cars with manual transmissions. A shift lock prevents turning the key without first pressing on the brake.
  • Most cars with manual transmissions have a form of lockout that prevents accidental engagement of the reverse gear.

    To summarize:

  • There is visual, auditory, proprioceptive, and tactile feedback on the state of the transmission.
  • Drivers are trained to put the car in neutral when starting the car.
  • There are two forms of physical lock out to prevent unintentional engagement of the transmission. and yet, drivers make mistakes.

    The problem is real, but I would rephrase it as:

    How do you prevent a car from starting to move in a direction the driver did not intend?

    Research on the causes of unintended acceleration is relevant here. For example, the evaluation of the problems with Toyota vehicles or Audi's in the 1980s. Lack of awareness of the mode of the car's transmission is not the only cause. Also, the problem is not restricted to cars with manual transmissions.

    BTW, Nissan attempts to solve this problem for parking situations.

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    • "How do you prevent a car from starting to move in a direction the driver did not intend?" encompasses a whole suite of questions. Answering it would involve answering: (1) what are the causes of unintended acceleration? (2) what are methods of preventing unintended acceleration? (3) what makes these methods effective? (4 and more) For each of these methods, what can be done to improve it? To give the question a scope appropriate to this site, I focused in on one of these methods. May 9, 2013 at 15:32
    • The context I provided to give the question some meaning shouldn't be interpreted as implying that improving the feedback of mode alone will solve the entire problem posed in that context. If you'd like to ask one of the other questions in a separate thread, that would help to establish more of the information necessary to solve the larger problem, but each aspect of the problem has its own answer, and thus belongs in a separate question on this site. May 9, 2013 at 15:33
    • @3nafish Ouch! A down vote on an answer that wasn't really an answer but rather a comment whose intent was to add information about a possible answer to the question. A bit harsh, IMHO. May 9, 2013 at 16:50
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      @3nafish The purpose of rephrasing the question was to point out the irrelevance of the answer to the question as a way for finding a solution to the problem. In other words, this question has no practical significance. Experts in this field have decided this question is not relevant. The solution to the problem will be found through other means. May 9, 2013 at 16:50
    • @3nafish The Nissan solution to this problem does not rely on providing any new information to the driver. Rather than rely on the driver preventing their own skill-based error, Nissan infers the driver's intent by examining the objects around the vehicle and the vehicle's speed. Nissan does not provide more information to the driver because it will not solve the problem. May 9, 2013 at 16:51

    I would argue that when driving a car, which gear you are in other than when you are in a standstill isn't important. What is important is whether you need to change up or down a gear.

    Although and extreme example, there were extensive tests on this in auto racing, and it was determined that the only information that a driver needed was whether he needed to change up or down a gear.


    How about looking at it from a completely different view? Don't allow the car to start unless it is in neutral/park and the brakes are on. That eliminates the problem altogether: the car won't move when it first starts, and the driver has to put it in the proper gear after starting.

    (Isn't that the way it works anyway? Or is that just how I always use it?)

    • That isn't the way it works. There is typically an interlock on the clutch - you must depress it to operate the starter - but not on brakes or gear.
      – nobody
      Apr 24, 2014 at 0:29

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