Zach Winkler was a senior at the University of Missouri when he began to notice that a lot of women at his school felt unsafe. Moreover, the hundreds of blue poles around campus -- affixed with buttons to call security in case of an attack -- weren't solving the problem. When he looked at data released by the school, he noticed that students rarely used the buttons.
"If you're scared, then you're not going to want to run and stand at a pole," Winkler explains to The Huffington Post.
So, he rallied three friends to help build a smartphone app that students could use quickly and quietly to summon help. The developers loaded their creation into Apple's app store as an experiment.
That was two years ago. Since then, their app, SafeTrek, has established itself in the increasingly crowded space of personal safety apps, garnering over 250,000 users -- nearly all of them young women -- across the United States.
To use SafeTrek, you open it during your walk home, for instance, and keep a finger on the screen's sensor, a process the company calls "hold until safe." Removing your finger triggers a screen asking for a four-digit code. If you enter the code, that's your signal to the app that you've made it home safely -- if you don't, SafeTrek calls the police and sends them to where you are.
Though mobile phones already make it pretty easy to call 911 for help, an operator might have trouble pinpointing your location if you're in a situation where you can't speak. Operators can use positioning data from phone towers, but that isn't always precise. Apps like SafeTrek, however, can use your phone's built-in GPS to find your exact position and convey that information to police.
Similar services -- like Guardly, Circle of 6 and Panic Guard -- use GPS or other mapping systems to allow friends and family to track you. Others, like MyForce, employ a separate security team to respond to calls. There are even digital panic buttons, which turn your phone into a screeching alarm if necessary.
Most of these services are targeted toward women, capitalizing on the fact that a lot of women feel scared while walking alone at night. Ninety-five percent of SafeTrek's users are women, and most of them are young -- about half the app's subscribers are 18 to 24 years old, and 20 percent are between 13 and 18. The app charges its users $3 per month.
People who use SafeTrek are often drawn by a specific concern. For example, after a realtor was killed in Arkansas last year, Winkler noticed realtors across the country signing up for the app.
Yet, walking down the street with your finger glued to your glowing cell phone screen seems like a conspicuous way of managing your personal safety. I asked Winkler if he felt that the process of using the app might exacerbate his users' fears.
According to Winkler, a lot of users already report experiencing post-traumatic stress disorder or extreme anxiety -- it's what draws them to subscribe to the app in the first place. "What we've found is that just holding the button helps relieve a lot of anxiety," he says.
A map of SafeTrek's activity shows hot spots around the country where people are using the app.
Jessica Pruehs agrees. She first downloaded SafeTrek while attending a community college in Huntsville, Alabama. Living alone, "I felt like I needed something," she says.
The app came in handy one night when her doorbell started ringing repeatedly. As she walked down the stairs, she drew up the SafeTrek app and put her finger on the button. No one was at her door, but when she started walking back upstairs she heard someone trying to break in. That's when she released her grip.
When the police arrived, they didn't find anyone at her house. But that hasn't stopped Pruehs from keeping the app handy as a precaution, which she does every night while walking her dog. "It just makes me feel better," she says.
As part of its latest project, the SafeTrek team is plotting the 7 million points of data the app has gathered thus far, locating hot spots where people often feel unsafe. Their hope is that this info could be used by police departments or campus security.
"Maybe it's installing an extra security light? Maybe it's more security patrols? Either way, there should be a way to make people feel safer," says Winkler.