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The form factor of this panel was heavily debated in our early planning. Having it be so vertical may limit the number of users that can concurrently access the panel, if the lobby is crowded. We developed a horizontal version of this, but it wasn’t recognizable enough as an elevator floor-selection panel. Given that our primary obstacle in this project is training people to treat this panel as a floor-selection panel, we opted for a familiar vertical button layout.
We also had to decide whether to use colors or letters to identify elevators. Using colors would allow users to identify their elevator from a distance. Colors are also easier for users to remember in the short term than letters, which is why they are used to distinguish floors in parking structures. Letters, on the other hand, remove all ambiguity in the case of a building with a very large number of elevators. They are also more accessible to the color-blind. We opted to use both letters and colors to represent floors. While this slightly confused one of our testers, the benefits of using both letters and colors are worth the slight decrease in simplicity.
The second part of our interface is right outside the elevator, above the door. This display contains a directional arrow indicating which direction the elevator is moving, an array of numbered circles with one circle corresponding to each floor, a dynamic ETA for the elevator, and a scrolling list of the floors the elevator will be traveling to. The first part of this interface the user will be exposed to is likely the array of numbered circles; each circle corresponding to a floor the elevator will be traveling to glows in the color of the elevator. This allows the user to identify their elevator by color from across the room. While the large scrolling list of floors usually makes it clear to the user where the elevator will be traveling, in the case of a single elevator visiting a large number floors the glowing circles will be more useful, as the user will not have to watch the scrolling text until their floor appears (or does not appear). The glowing circles are also an optimal indicator for users who travel to the same floor in the building very frequently; they will eventually memorize the position of the circle corresponding to their floor and will be able to confirm they are at the correct elevator at a glance. The ETA displayed above the elevator is made possible because we’ve moved floor selection outside the elevator. It may increase dynamically as more users select floors, but any kind of indication of waiting time should decrease frustration and impatience in users, and our system will over time get very good at predicting ETA as it collects more data. The arrow indicating the direction of the elevator will be necessary in buildings that are short on elevators, because a single elevator may be assigned to both a floor above the user’s current floor and a floor below the user’s current floor. In this case, frequent users will note the direction of the arrow and won’t board the elevator while it is going in the wrong direction. It is not catastrophic for users to ignore this arrow, in the worst case they will have to ride the elevator for a little longer than necessary.
Initially, we chose to show a single arrow indicating the current direction of the elevator. However, we found that our users were confused by this. Many did not seem to realize the purpose and we had several comments that the arrow was unnecessary. Since an elevator may need to go in one direction before it can take a user to a floor in the other direction, we included the arrow as an indication to the user that the elevator would not be headed to their floor immediately and that it might make sense to wait for the elevator to return before getting inside. We thought this was important feedback to give to the user so we elected to show two arrows at all times and highlight the one that represented the current direction. We thought this would better indicate there are two options.
We also considered how best to indicate which floors the elevator would travel to. When an elevator needs to travel in both directions, it may make sense for users travelling to a floor in the second direction to wait until the elevator returns to get in. We wanted to include floors in the second direction in the interface so users would know they had gone to the correct elevator. However, we did not want to display them in exactly the same way as floors the elevator would travel to immediately. While the arrow should ideally indicate to users which floors the elevator will go to first, we found that users were confused by the initial arrows, so we wanted another way to represent the fact that the elevator would not travel immediately to those floors. We decided to highlight the floors in the button array but not display them in the scrollbar. This clearly indicates there is something different about those particular floors. Seasoned users will know immediately what it means, and the discrepancy will prompt new users to look further at the interface at which point they will hopefully discover the arrows and be able to figure it out.
IMPLEMENTATION
Three interfaces make up our elevator system, one for the lobby, one above the elevator, and one inside the elevator. For clarity, we have grouped our implementation details by the relevant interface.
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