I'm designing a prototype for a mobile app that allows you ask for help inside a public transportation (bus or streetcar). The goal is to alert all passengers that someone needs help inside the same car as they are (so the user doesn't need to contact people individually). Help can be something as simple as the person is feeling sick and needs to a place to sit or someone is harassing them.

The button sends a distress signal to everyone in the car (they will get a notification as a personal message). I will display via AR where the person is located (another feature that is not on this prototype) but I'm wondering on whether or not I should place a button or a toggle for "request help". I initially thought about a toggle because it allows you to turn it off if the problem was resolved. I have another version which I replaced "request help" for "send distress signal"

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"AR view with distress signal"

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  • are you alerting the passengers, or the authorities / conductor / driver of the train? With a button, you can prompt action to the authorities, while driving a notification to your fellow passengers that help has been called. Hopefully my answer below provides some clarity.
    – Mike M
    Jun 11, 2018 at 21:12
  • Alert passengers only. From my research alerting authorities doesn't work (Elerts Corp app failed in many US cities). The idea is to get other people inside a car to help others. Most harassment is solved by people inside the same bus/train. Jun 12, 2018 at 5:36

2 Answers 2


Toggle means something long running. What should user expect when the toggle is on? Will it send "Request Help" message only once, or 100, or 1000 times? Will it send "Request Help" messages without any limit even if user forgot to switch it off? Toggle in this case is counterintuitive.

Better would be a button. A single press sends a single "Request Help" message. This is more natural. It is easier to understand and to use.

  • makes sense! but how do I flag that the help is not needed anymore? a cancel button on the side while the request help is active? I am trying to do in a very automated way to avoid people messaging each other. Jun 12, 2018 at 5:48
  • You can provide a status message outside the button. You should also definitely include a Cancel button for those cases where someone accidentally triggers the button, unless the app asks for confirmation. Similarly, provide Cancel to the response mechanism as well. And consider keeping the "alert" active for some time. It would be unfortunate, for instance, if someone were to "respond", but then be unable to or choose not to, leaving the person in need unassisted.
    – wootcat
    Jun 12, 2018 at 13:48
  • @Daniel Vianna: Button will be pressed once. A single message will be sent. That is why there is no situation "not needed any more". It is vise versa. If someone supposes that nothing happens, he kan press button once more. Compare this to calling 911. You are not staying on the line 15 min until help comes. You call once. Wait. If you see no help in a reasonable time, you call them once again.
    – mentallurg
    Jun 13, 2018 at 1:26

Use a button to encourage action. Use text to show status of the event or issue.

Once the issue is flagged by the system, the button area (or next to it) can change to a resolution or status message.

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The important thing in this app, is to show context and state for people in the same physical area. Someone sitting right next to a person in distress can clearly see what's going on; this does not mean that others at the end of the car can.

Avoid the bystander effect (no one does anything)

individuals are less likely to offer help to a victim when other people are present. The greater the number of bystanders, the less likely it is that any one of them will help. Several factors contribute to the bystander effect, including ambiguity, cohesiveness and diffusion of responsibility.

What you want to do in this situation is to give people situational awareness, and call for action if no one else has. Remember; if the situation is someone getting harassed or feeling threatened, they may be too scared to call for help. Someone out of the field of view of the assailant can discreetly call.

What you don't want is everyone just assuming that someone else has (or will) alert the authorities or help.

A toggle vs. a button

A button is a discreet action; a toggle is often a view preference or state toggle.

If the goal is to allow action (calling for help), use a button. The disabling of the button (combined with a clear message that help has been called for), will allow users to understand the state of the situation.

  • "The important thing in this app is to show context and state for people in the same physical area. Someone sitting right next to a person in distress can clearly see what's going on; this does not mean that others at the end of the car can." ........They could see in the AR/3D map (I made some modifications on my post to show that screen). In your suggestion Mike, the grey button is "pressed" state which can be clicked to return to "normal" state? or do I need an additional ( X ) mini button to cancel the action? I want to this as much automated as possible with minimal user input Jun 12, 2018 at 6:14
  • Maybe "Help is on the way" isn't the best solution, unless somebody actually can accept the call for help on their device. I definately need a cancel option, and the logical thing to do would be the same button, but with other text and color.
    – Anders
    Jun 12, 2018 at 10:00

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