Interaction design

In earlier posts we wrote about the usability of one particular parking meter in the Netherlands and proposed two interface alternatives. After discussing both concepts one interface has been further developed.

(click for larger version)

What is in it?

The interface has a hierarchy from top to down, which is also supported by numbering the four necessary actions the user has to take. The user can stop at all times by use of the ’stop’ button. By placing the stop on top the user is informed that the action ’stopping’ is not associated with any of the four actions but can be activated at any given time. The interface gives feedback at all times to the user about his actions. Now let us have a closer look at each step.

0 Getting informed

The days and hours of ‘paid parking’ are displayed as graphic bars. Instead of fully writing the text which has to be read this can be understood quicker. The stop button is placed in the top to emphasize to users that they can stop at any given moment and that ’stopping’ is not associated with any of the four actions.

(The days and hours of parking time are shown in graphic bars)

1 Choosing the street of the parked vehicle

The user has to choose the location of the parked street. In this case the buttons are associated with the street names. Also the price and maximum parking time is given in this step unlike other parking meters that display all the information in the beginning. When a street is selected the with edge around the button will become green to inform the user about this selection.

(choosing the parking location is confirmed by a green color around the edges)

2 Choose desired parking time

Users can set the parking time in different ways; by duration and by the time they want to leave. This is unlike most other parking meters that choose either one of these methods. It is likely people plan their parking time different, and they can set the parking time in different ways accordingly.

The initial state shows the current time in the ‘expires’ state’ which is logical since a ticket would expire at the same moment. The ‘duration’ and ‘price’ field are set to zero since no parking time has been chosen.

After choosing the parking time by turning the wheel the displays show the ‘duration’ of parking, the time the parking ticket ‘expires’ and what the ‘price’ would be.

(The chosen parking time is shown in two different ways, ‘duration’ and ‘expiration time’)

3 Pay price with coins or chipknip

The amount that has to be paid can be seen live on the display. If the user decides to pay with coins he can start directly by entering coins. When the user want to pay with chipknip he can insert the card and the amount will be charged as soon as the card is fully inserted. The line in the middle should emphasize the user has to choose between payment methods.

(The remaining amount shows live which amount still has to be paid, now 50 cent has been paid and 20 cent is remaining)

4 Take ticket and change

The icons should notify that the ticket and change can be taken at the bottom. When the receipt is printed (and if change is given) a light in the chamber will start blinking and a beep will be given to notify the user of the available receipt and change.

(When the receipt is printed and change is given the chamber starts blinking and gives one beep to notify the user of the available receipt and change)

Why could this interface be better?

First of all it is not proven that this interface is better, it should be tested with users to make such a firm statement. But I am confident saying this interface is likely to be a lot better because of its top to down hierarchy, the continuous feedback and the control users have all the time.