Never has it been easier to reassure your mother that your nightly walk home will be a safe one.

SafeTrek, a free app available for iOS and Android devices, allows users to have their local police on speed dial when they feel unsafe because, as its app store tagline reads, “In a real emergency, you don’t always have time to pull out your phone and dial 911.”

The app, created by a group of University of Missouri students last year and featured on Good Morning America in April, is straightforward and user-friendly. Upon downloading it, you simply enter your first and last name, your phone number and a 4-digit PIN number into the introductory page’s designated slots.

Each step of the simple-but-brilliant concept is displayed both upon your first use and when you click the “info” button on the in-app home screen. As ovalesque cartoon characters explain in the demo, before setting out on a potentially unsafe commute, you simply open the app and follow the only visible directions: “hold until safe.”

When the blue, U-shaped button in the center of the screen is pressed and held, the device vibrates, and the button pulses and turns red. Releasing the button summons a keypad and a timer that counts down the ten seconds in which you must enter your PIN number.

If the code is not typed into the keypad in the designated amount of time, according to the app’s online description, local police are contacted and informed of your location through the app’s GPS tracking system (yes, you have to agree to let the app track you when the button is being held, but the tracking evidently ceases when the button is released and the correct code is entered).

Downloading SafeTrek is an easy precaution to take for those of us who have to walk alone at night through unsavory parts of town. Letting go of a button would be simpler than fumbling with pepper spray or a whistle in case of emergency, and the 10-second countdown ensures a quick response.

According to user reviews on the Apple app store, if the code is not entered before the provided ten seconds are up, a text is sent to the phone to confirm that an emergency is taking place (which is reassuring, since accidental activation could potentially be a problem for those of us who walk alone at night while juggling armfuls of belongings). If you do not reply within seconds to confirm your safety, though, the app automatically dials 911 and your location is given to the local police.

SafeTrek currently ensures service anywhere in the United States, so next time you need to take a nightly stroll, remember that that you have a better, safer option than calling a sleeping friend or having your phone in your pocket to be dug out at a moment’s notice.

Having the reassuring glow of the SafeTrek app literally at your fingertips is essentially having 911 on automatic speed dial—and what could make your mother sleep better at night than that?