What is a personal safety alarm?

How a personal alarm works

Most alarms are battery powered and about the size of a car key fob. A common design uses a pin on a lanyard: pull the pin and the siren starts; push it back in to stop it. Others use a button or a sliding switch. Brown University's public safety office, which gives free alarms to its students and staff, describes exactly that design: pull the pin and the alarm sounds and the light flashes, then insert the pin to stop it. Brown says the alarm can be used to call for help, draw attention to an unsafe situation or scare off an attacker, and advises testing it periodically and replacing the battery as needed.

Because it is purely local, it works anywhere, with no signal, account or subscription. That is both its strength and its limit.

When it helps

East Carolina University's police department advises carrying a noise-making device, such as a shrill whistle or hand-held alarm, and having it ready to use. A sudden, unmistakable noise changes the situation: it turns heads on a quiet street, can bring a neighbor to a window, and may make someone think twice.

For runners and walkers, it is most useful in populated but quiet places: a residential street before dawn, a park path, a parking lot after a late shift. Our guide to personal safety alarms for runners covers choosing and carrying one in detail.

• Someone approaches you in a way that feels wrong
• You think you are being followed and want to make it obvious
• You are hurt near a road or path and want passersby to notice you
• Something feels off as you walk to your car in a parking lot or garage at night

A real-world example

A walker cuts through a park at 6 a.m. and notices the same man behind her for the third block. She pulls her alarm from her waistband clip, triggers it and holds it up while heading straight for the lit coffee shop on the corner. The noise makes the situation public: the barista looks out, a dog walker turns around. She then calls someone she trusts from inside. Our answer on what to do if someone follows you while walking covers the steps after that.

Now picture the same walker on a wooded trail two miles from the road. The alarm works just as well, but nobody hears it. This is where it needs a partner that reaches people far away.

What an alarm cannot do

Noise only helps if someone hears it. On a remote trail, a gravel road or a wooded park at night, there may be nobody within earshot. The alarm will not tell anyone you need help, and it will not tell anyone where you are.

It also needs you to use it. If you fall and hit your head, or collapse from heat, you will not pull a pin. And an alarm buried in a zipped pocket is hard to reach in a panic.

It is not a replacement for calling 911. If you are in danger and can call, call.

Personal alarm vs SOS alert vs fake call

An SOS alert in a phone app sends a message to specific people, usually with your location, but makes no noise where you are. A personal alarm makes noise where you are but tells nobody far away. They solve opposite halves of the problem. A fake call app is quieter still: it gives you an excuse to leave before a situation escalates.

Some phone apps include a built-in siren, but you usually have to unlock and tap to start it, and a phone speaker is generally not built for volume the way a dedicated alarm is.

Choosing and carrying one

Look for a loud, piercing tone, a trigger you can find by touch, and a clip or wrist loop that keeps it on your body. Brown notes an alarm can be carried in a purse, a pocket or on a belt; for running, a waistband or pack strap is easier to reach than a bag. A flashing light helps at night. Test it before you rely on it, somewhere that will not alarm the neighbors, and replace the battery on a schedule.

Practice pulling it once so the motion is familiar. If you run or walk before sunrise, our answer on staying safe walking alone at night pairs well with this.

Pairing an alarm with Holler

Holler does not include a personal alarm or siren. What it adds is the part an alarm cannot do: telling the people who care about you. Share a private live link with your Guardians before you head out, and if something happens you can press SOS to notify them with your location by email and push.

If you cannot press anything, an optional return time sends them an overdue alert five minutes after your deadline passes. For running-specific advice, see what to do if someone follows you while running.