Ohio State University freshman Liz Kallmeyer has one rule when leaving a night class alone: Call a friend at the dorm and, if possible, keep her on the line until she's safely home.
"If anything happens, someone I trust will know about it," said Kallmeyer, a 19-year-old psychology major from Grove City.
While no one has tracked the numbers, experts believe that more people -- particularly young women -- are turning to their cell phones for personal security because they can connect them to anyone, anywhere at any time.
But college officials and police warn that talking on a cell phone can make people an easier target.
"It's a false sense of security," said Rick Amweg, Ohio State's assistant police chief. "If something happened and you screamed 'Help!' the person you're talking to wouldn't know exactly where you were and couldn't call emergency officials as quick as you could."
While he's certain it's an increasing phenomenon, his advice is, "Don't do it."
Instead, walk with a friend or in groups, or use the student escort service, and stay in well-lighted areas.
"The biggest problem with talking to a loved one or friend on a cell phone while walking at night is that people get so caught up in their conversations, everything else fades into the background," Amweg said.
But a wireless provider said talking on a cell phone is no more distracting than talking to a companion or listening to music, and many people carry them specifically for emergencies.
Nationwide, more than 240,000 emergency calls are made daily by people using cell phones, said Laura Merritt, spokeswoman for Verizon Wireless.
To avoid losing focus on her surroundings, Kallmeyer says she keeps her calls short and to the point. "I tell my friend where I am, what route I'm taking back and if I see anything suspicious along the way," she said.
Most of the time, Kallmeyer tries to keep her friends on the line until she gets where she is going. Other times, she tells them her destination and how long it should take her to get there.
Nicole Guy, a senior education major at Ohio State, would rather be with a friend than use her phone if she is out after dark.
"While I partially know how to defend myself, what if someone was following me and caught me off guard?" said Guy, a 24-year-old Dayton native.
Walkers can lessen their risk by being alert and prepared for the worst, said Amanda Ford, Columbus police spokeswoman.
"We wouldn't want to tell someone, 'Don't talk on your phone' if it makes you feel safer," Ford said. "But use common sense, and avoid putting yourself at risk."
Wendy Powell, 34, of Westerville, said carrying a cell phone while walking her Jack Russell terrier puppy in Sharon Woods Park at dusk offers psychological comfort.
"Whether I'm talking on it or not, I find I'm more likely to walk tall, look people directly in the eye and feel in control of the situation," Powell said. "I can't explain it, but it's empowering."
At Ohio Dominican University, officials worry that students are lulled into feeling safe because the campus is "serene and self-contained," said Drew Klein, vice president for student development. "It's easy to forget that anyone, even the most dangerous person, could walk or drive onto campus at any time."
The school handed out safety whistles to freshmen at orientation this year and to other students through classes and other programs. Next year, the college plans to add two more blue-light emergency phones that directly connect students to security officers, Klein said.
Ohio University officials suggest that students think of their cell phones as a tool, similar to pepper spray, to help make them safer.
"Just because you have it doesn't make you Superwoman," said Mark Mathews, OU's assistant police chief.
He advises students that it's better to be too careful than not careful enough.