Controls on moving controls?

Question

It hit me today when driving home from work turning right in a highly busy crossing. I wanted to lower the music volume but couldn’t find the control without looking. On previous cars I’ve owned, the controls were fixed, positioned behind the steering wheel, so when I made a turn I could still find them without looking. On this new design, it was impossible.

But I can imagine driving on a highway, having the controls clearly visible right in front of you is very convenient. No way to miss anything and easy to control at high speed, without looking.

Maybe I’m just not yet used to the new position of the control, or it’s contextually bad having the controls positioned on another moving control in busy city traffic. But in general, do we recommend controls on moving controls?

Answer 1

There is no answer to the general question because there are use cases where the answer is yes and use cases where the answer is no.

For example, there seems to be agreement in this thread that controls on a steering wheel for a car is not ideal.

However one can argue that controls on the joystick of an F16 are not only a good idea but one could not safely maneuver the aircraft and engage weapon systems at the same time without it:

As you can see in this diagram the joystick (labeled "sidestick controller") has a primary function of controlling the aircraft's attitude and secondary controls for setting trim, weapons systems, display systems, autopilot, and defensive countermeasures.

On the other side of the cockpit the throttle has a primary function of controlling the engine's thrust with secondary functions for radio communications, radar, etc.

In this configuration both hands are engaged with primary flight functions while individual fingers are manipulating controls on these moving controls to engage secondary flight functions or primary weapons functions.

In civilian aviation you have controls on moving controls. The primary jump ship at my drop zone (a Cessna 208B Grand Caravan) has a yoke with a radio button on the upper left side which allows the pilot to engage the radio to communicate with air traffic control without taking his left hand off the yoke leaving his right hand free to adjust trim or throttle (both primary actions necessary for maintaining flight).

With many broad design questions the answer is often it depends.

However in the case of aircraft, neither a joystick or a yoke have the same limitations as a steering wheel (their range of motion never puts the user's hand in a position where they can not easily engage the secondary controls). So the primary arguments against controls on controls for automobiles do not apply to aircraft. As a result, controls on moving controls are a good idea for aircraft.

Answer 2

As per an article I found, Why interaction in motion is hard, the answer is no. To quote the reasons given in the article:

Movement and attention Focusing on the device can reduce our ability to respond to events occurring on the road, and cause safety issues. This issue of a limited ability to pay attention to multiple activities generalises to other types of movement – for example if we are running hard it is harder to pay attention to interactive systems, and if we are paying attention to an interactive system, it is harder to give our full attention to what we are running over.

Physical constraints of movement Movement activities can be physically constraining in ways which limit our ability to interact with devices whilst moving. This can be for several reasons: In some activities, the activity itself demands some kind of physical manipulation of equipment,the way in which we are currently moving may reduce or increase the amount we are constrained to manipulating this equipment at any point.

Physical, digital and social terrain When we are moving, the terrain we are moving over has a large amount of impact on how much we are able to pay attention to a device, and how physically constrained our movements are. Designing for movement means designing to take account of the fact that all these factors may change whilst interactions are ongoing.

However with regards to design for controls of steering wheels on cars, as drawtheweb pointed out you might have dealt with an extreme fringe case of trying to do the one action where the system would have failed i.e reducing the volume and turning at the same time. However if you look at your second picture,you will realize the placement of the buttons was done with some thought i.e they are placed closest to you to use your thumbs without having to take your hand of the steering wheel. Hence in your case, I think the one use case where this could have failed was not considered or not catered for but the general design for was cases where you would just be driving on a straight road and then changing the volume and and not while performing a sharp turn. However this article How bad usability damaged my car does show that such a situation can lead to serious usability issues if not catered for :

Here’s why: The 2 horn buttons on the steering wheel of my Acura Integra are very small and mounted on the left and right sides of the inside of the steering wheel as shown here.

The problem is that when I went to hit the horn button it wasn’t there because the wheel was turned which put the horn buttons in an abnormal location as shown here. I was hitting all over the steering wheel but before I could find one of the horn buttons the car hit me.

Answer 3

Don't ask "is this a good idea", ask "is this better than the alternatives?"

What's my alternative to controls on the steering wheel?

• Controls on the dashboard! But...I have to take my hands off the wheel. That's even more dangerous than waiting while you're doing a turn.
• Touchscreens! Worse, I have to look at these things. Wheel controls are physical and can be used without sight
• Controls around but not on the wheel! Same problem as the dashboard, plus there are usually already levers around the wheel; almost always the headlights/turn signal controls, and sometimes the gear changer.

Is the steering wheel really that bad?

• 95% of the time it's in a straight or slightly turned position where "thumb" buttons are easily accessed
• When your thumbs are at the standard positions it allows you to operate the controls easily, without looking and without moving your hands from the wheel
• Steering wheel controls are almost exclusively non-vital functions. The horn buttons in Mervin's example are a nightmare, but just because you can make a design bad doesn't mean all possible designs like it are bad. Volume, next song and similar tasks aren't time-critical and can easily be deferred until the wheel is upright.

In the general case of course "controls on other, moving controls" is a bad idea; that's why they're extremely rare. But that's mostly because there's almost never an actual reason for there to be controls on controls. In the steering wheel example there is, and it actually provides major benefits over alternatives. Generally having a button that emits an extremely loud noise at will for no mechanical reason isn't a good design decision either. Cars have those, too, and they're actually pretty important.

Answer 4

It's not just that you drive a Peugeot, there are genuine limitations given what the driver is willing to pay for said feature.

I would consider the desperate need to turn down the volume while in the middle of a turn a fringe-case. I might go as far as saying that turning itself is a fringe case. You spend way more time with the car moving directly forwards than you do in a turn.

I'm sure there is a way to design around this, but sometimes the implementation is 'good enough' given the relative value to the user and how often a scenario is encountered.

Having a centre console of the steering wheel not rotate just so certain controls remain in a fixed position is a bad idea in the context of driving. The rotation of your peugeot logo speaks volumes in regards to your current trajectory. I'm sure there are alternate options, but over-designing this will only increase the cost to the consumer with little benefit to the manufacturer with regards to units sold or accidents prevented.

I've never heard of a volume control in a fixed position behind the steering wheel, but that could be a European thing. In North American vehicles a fixed location for the volume is normally sitting on the centre console between the driver and passenger.

Edit: To answer your question, no I don't think it's generally a good idea to put controls on other moving controls, especially when the user's attention on the primary control is important in keeping them out of trouble. Keep in mind that volume control on a steering wheel is a feature that sells, and sometimes selling circumvents usability.