Civil Engineering Reference
In-Depth Information
and touch sensitive, thereby violating all my expectations; poor affordances in design! It
is surprising that the design engineers of X2000 could not get the toilet-user interface
right. Compared to the engineering innovations in designing the high-speed train, this
would seem a very trivial issue. But then we forget: few people have the skills to think of
human factors design.
FIGURE 6.1
Illustration of the control problem in the X2000 train.
6.2
APPROPRIATENESS OF MANUAL CONTROLS
Manual controls should be selected so that they are appropriate to the task and intuitive to
use. Some controls can make a task easy to perform, whereas others make a task difficult.
One way of analyzing control requirements is shown in Table 6.1, where controls are
classified by the number of settings and by the force required to manipulate the control.
For example, if a control does not require much force and there are only two discrete
settings, the recommended types are toggle switch, pushbutton, or key lock. If there are
several control settings, a rotary selector would be a good choice.
If a large actuation force is necessary, one should select a control where it is easy to
apply force. Finger-actuated controls will not do. Hand pushbuttons, foot pedals, levers,
or cranks could be used.
Note that the controls in Table 6.1 are all mechanical and the rules were published
over 30 years ago. Presently many controls are programmed and they have become
