Title: Windshield Wiper Control Redesign


A car is a context in which activity is determined entirely by human - computer interaction. Driver and passengers alike, are confined to the affordances and constraints given by their particular physical placement within the vehicle. These affordances and constraints range from the location of the ignition and the arrangement of the alphabet in the navigation, to the inclination and heating of the seats. By refining existing controls within the car based on practical observation, it is possible to gain insight on how to take a more human-centric approach to designing the interactions. There is an opportunity for design in any observed instance of mistake, confusion, or discomfort. In the case of the car’s driver, a mistake or lack of understanding in the function of a control can be disastrous. Therefore, to design responsibly, vehicle controls need to be placed, designed, and communicated with great care and practicality.

In the case of the windshield-wiper control, all functions related to the windshield wiper have traditionally been isolated and confined to a single control with multiple, overlapping states. By generating state diagrams based on the existing controls, it is possible to reverse-engineer the mental models the original designers intended for the users. What we find, is that although each state is labeled, the physical distance of the control from the driver does not provide for instantaneous clarity while driving. The overlap and inconsistency of the triggers paired with an excess of modes for which there exists only non-specific feedback opens up many opportunities for improvement. 

Project Brief

The challenge of this project demanded for the conception, or improvement of a user control within the environment of the car. The aim was to identify and resolve critical problems in the human-computer interaction related to clarity, intuitiveness, practicality, responsiveness, usability and communication.  


Analysing the Existing Control

To identify the limitations, and consequent design opportunities in the current control’s condition, user observation and critical analysis of the state design were necessary. The most obvious short-comings surfaced as a result of observed instances of hesitation and misunderstanding. By isolating, and situating these moments of friction within the context of the state diagrams, it was possible to understand where the disconnect between the preferred user action, and the control’s mental models occurred. For the windshield wiper, these disconnects were a result of problems in both the physical and the state designs. The physical design, as well as its placement, lead to issues including limited visibility, and insufficient tactile contrast for the number of functions and triggers condensed within the single control.

The most prominent issue users encountered was attributed to uncertainty in regards to what state the control was in once it had been activated. For instance, if the driver wished to switch off the wipers and did not remember if the lever was left in HI / LO or INT, they would switch from HI into LO and only receive feedback of their mistake several moments later when the wiper returned at LO speed. By turning to the state diagrams, this problem could be pinpointed to the outmoding of the control and a lack of mode-specific feedback. Several modes produced the same, or very similar outcomes and the user had no means of discriminating between them other than by referring to the poorly visible demarcations on the control itself. 

The labelling and organisation of the control too, posed difficulties for the users. The INT mode for example, appeared on both the lever controlling the front wiper, and the dial controlling the rear. For the front wiper, activating this mode on the lever allowed the user to then use the central dial to select between five incremental wiper speeds. For the rear dial, INT simply stood for the faster of two possible speeds.


Solution Development

To create a more effective control for the windshield wiper, it was important to first reconceive the content and structure of the state diagram, and develop the physical design subsequently. The proposed re-design addresses the outmoding and non-specific feedback by reducing the number of total modes, and by organising them in a linear structure. By limiting the trigger format to dials, user action becomes more concise and natural than in the previous lever-dial system. The mental model tying together the front and rear control is made intuitive through symmetry, and visibility and accessibility is improved by placing the triggers on either side of the steering wheel. Giving the control a prominent placement in viewers field of vision, required overall attractiveness of the control to become another key concern in the control’s redesign.