Aster has two ways to raise the alarm if something goes wrong on a ride or run: a manual Alert button, and automatic crash detection, both available on a Just Ride and in an event.
Before anything else, the honest bit, and the app tells you the same thing the first time you open Alert:
An alert notifies the people watching your ride. It does not contact the emergency services, and it does not guarantee anyone will respond. It's an aid, not a safety device. Always carry your own means to call for help.
We call it "Alert" rather than "SOS" on purpose: the older word sounds like a guaranteed rescue is coming. Raising an Alert means exactly what it says, you're alerting real people. It never pauses, stops or otherwise changes your activity: your ride or run keeps recording and tracking exactly as before.
Who gets your Alert
- In an event, your Alert goes to the event organisers: it appears on their race-day dashboard with your exact location, and if nobody acknowledges it within a couple of minutes they're alerted again. It's handled discreetly: spectators don't see it. See Handling Alerts.
- On a Just Ride, your Alert goes to your watchers: whoever can currently watch your ride, your followers if you chose Followers & club, or whoever you sent the link to if you chose Anyone with link. Before you send, the app shows how many people that is. If nobody is watching (including if you started on Just me), it says so plainly: an alert would reach nobody, and if you need urgent help you should call your local emergency number.
There are no other recipients. Aster doesn't hold a separate list of emergency contacts, see Who gets alerted when you need help.
Sending an Alert
- While tracking, tap the amber Alert button.
- Read the one-off "this isn't a rescue service" notice the first time, then confirm Send alert? on the next screen.
- A 60-second countdown starts, with a large Cancel (I'm OK) button. Nothing is sent yet, this window exists so a pocket-tap or a change of mind never fires an alert. If you're sure, you can also tap Send now to skip the wait.
- If the countdown runs out uncancelled, your current location is captured and the alert is sent.
Once it's sent, the confirmation screen offers a one-tap Call emergency services button. If you need real help and have signal, that call is yours to make (999 in the UK, 112 across the EU); Aster can't make it for you.
A few things worth knowing:
- An Alert never ends or pauses your ride. You stay tracked, which is exactly what you want if help is coming, the people responding keep seeing your position.
- You can raise an Alert while paused. A mechanical or a cafe-stop incident still counts.
- False alarm? After it's sent, tap Cancel alert (False Alarm): the people who were alerted are told it's cancelled.
- If the alert can't reach the server (no signal), the app tells you clearly that your watchers have not been alerted, so you're never left assuming help is on the way when it isn't.
There's also a separate green I'm OK button to reassure the people watching if you've been stationary for a while and someone might be worrying. It's a proactive check-in, not part of the Alert flow.
Sharing your phone number
By default, an Alert carries your location but not your phone number. If you'd like the people handling your alert to be able to ring you, open your profile editor, fill in Emergency phone, and tick Show my phone number to safety-alert recipients. The number is revealed only alongside an Alert, it's never shown on your public profile.
Automatic crash detection
On both a Just Ride and in an event, Aster watches your GPS speed for the signature of a crash: moving at speed, then stopping almost instantly. The speed floor is tuned to the activity, roughly 20 km/h for cycling and 9 km/h for running, followed by a sudden deceleration. If that happens:
- An alarm sounds and your phone vibrates.
- The same 60-second cancellable countdown used for a manual Alert appears.
- If you don't cancel in time, an alert goes to your watchers or your event organisers automatically, same recipients and same rules as a manual Alert for the activity you're on. On a Just Ride it is marked as a possible crash; in an event it reaches the organiser looking the same as an Alert you raised yourself.
Kerb hop, dropped phone, emergency stop for a sheep? Tap Cancel (I'm OK) during the countdown and nothing is sent. Crash detection never stops your ride, if you did come off, your live location staying visible is what helps people find you.
What a watcher sees
If someone you're watching raises an Alert, a red banner appears at the top of the watch page, no login needed:
- who triggered it, and whether it was a possible crash
- their last-known location, as a link you can open in your maps app
- what to do: try to contact them first; if you can't reach them, call the emergency services (999 in the UK, 112 across the EU) and give the operator that location. Aster cannot call the emergency services for anyone.