Tag Archives: Usability

The Usability of a Toyota Prius


This is the gear shifter from a Toyota Prius, the 2007 model to be specific, which I drove while on a work trip. If you’ve never driven this car before, let me describe how it works:

  1. The shifter is spring loaded, so it always rests in the position you see it in now. You move it to the “D” position for drive and it returns back to the “resting position”.
  2. There is an indicator on the dash (not pictured)  showing you if you what gear you are in.
  3. If you want to put  the car in park, you push the park button that is light in the picture.

So from a user experience perspective, what are the usability issues with this setup? What’s good about it? And why?

Let’s look at it using some of the parts of a usability heuristic evaluation

Status & Feedback – Is it clear to the user what’s going on at all times?

  • Good: LED on the parking button helps provide feedback to the driver that they are in park
  • Bad: Only the parking button has an indicator to confirm correct selection. Now granted there is certainly a dash indicator too, but could you improve the user experience by having an indicator in both spots?

Relevance & Familiarity – Are you using language that is familiar to the user? Does it line up with other products the user might have encountered?

  • Good: “R”, “N”, “D”, and “P” are all familiar to the average driver, and using the full words for something this common probably isn’t necessary.
  • Bad: While most of the letters on the gear shifter are clear, the “B” option isn’t clear as to what it should do.
  • Bad: On most cars the park option is selected using the same controls as drive, so your average driver stepping into this car won’t know to look for a button. As I’ve told some of my employees in the past, you need a really good reason to break a UI standard, and it’s not apparent what that really good reason is. I’ll add that there might have been a good engineering reason for this choice, but if that is the case you have to be careful that convenient engineering decisions aren’t trumping good usability.

Consistency – Are you consistent within the product in where items like navigation are placed or how buttons look?

  • Bad: The use of a box on the park button is inconsistent with the other letters / options. Using a box helps emphasis, but the designers of this car already separated the park button out from everything else, so is it a necessary inconsistency?

For the items I marked as “bad” keep in mind that this is the perspective of a first time driver. Sometimes you want to optimize for repeat users, so these issues might not be deal breakers depending on your audience and how they interact with your product.

What other good or bad usability things do you observer?

The 10 Parts of a Usability Heuristic Evaluation

Jakob Neilson back in 1995 wrote that there are 10 principles to a usability. If you want to conduct a heuristic evaluation of your product these principles provide a great starting point. So let’s take a look at some questions that you can ask for each principle.

1. Status & Feedback

Is it clear to the user what’s going on at all times? Does your app or website occasionally show a spinning wheel without making clear what’s going on behind the scenes? When the user clicks on something, are you giving them feedback that you received their input and are working on it?

2. Relevance & Familiarity

Are you using language that is familiar to the user? Would someone in your target user base be familiar with the labels you’ve used? Does it line up with other products the user might have encountered?

3. Control & Freedom

Can the user click around the app and explore, or are they forced into a rigid workflow? If you have a series of steps, can they go backwards in the process without loosing progress?

4, 5, 6 – Error Prevention & Handling, Help

What happens when something goes wrong? Are the error messages helpful? Are you warning users about potentially destructive actions (i.e. deleting something)?

7. Consistency

Does your product follow existing conventions (i.e. double clicking vs single clicking)? Are you consistent within the product in where items like navigation are placed or how buttons look?

8. “Don’t Make Me Think” (Recognition vs Recall)

Do you provide relevant instructions to the user at the appropriate time (i.e. displaying password requirements next to the password field). Do you require the user to reenter information unnecessarily?

9. Flexibility & Customization

Do you allow the user to save common actions, settings, or other personalizations?

10. Pleasant Simplicity

Is extra information being displayed (or requested) that could be put elsewhere or in the case of user input be determined in a simpler fashion? (i.e. on a mobile device using GPS instead of asking for a zip code).

Obviously you might want to expand on these for your specific application or business need, but this list get you started!