A year ago, if you had asked Pamela Wheelock how long it would take to tighten building security on the University of Minnesota's sprawling Twin Cities campus, she would have said: five years.

At least, that was the original plan, according to Wheelock, the vice president of university services. But that changed last fall, when a sudden spike in robberies and sexual assaults on and off campus got everyone's attention.

Since February, the U has converted 142 campus buildings to electronic-card access — which means that people must use their university IDs to come and go after hours. It has also shrunk the hours that buildings are open to the public.

"Instead of five years, we did it in five months," said Wheelock.

In a string of attacks last fall, thieves often targeted students walking alone or late at night, making off with their cellphones and laptops. Two incidents were reported in broad daylight on the West Bank campus: a robbery in the atrium of the Carlson School of Management and an attempted robbery in Anderson Hall.

In the wake of those attacks, the U has spent about $3.1 million on a campaign to make the campus and its surrounding neighborhoods safer, officials say.

Among other things, the U hired three police officers (for a total of 50), added 16 security cameras, installed new and brighter lighting along main routes on campus, and worked with the city of Minneapolis to increase lighting on nearby University Avenue, Wheelock said.

And starting next week, the U will run a weekend bus service, the University Avenue Circulator, until 2 a.m. along University Avenue and 4th Street SE., where many off-campus students live. The U is even hiring some student monitors to escort passengers to their homes, Wheelock said. That's in addition to the U's free shuttle service, Gopher Chauffeur.

This week, too, freshmen are getting an earful about safety. The message, says Wheelock: "You're living in a big urban area now. It pays to pay attention to your surroundings."

maura.lerner@startribune.com