After a long night studying at Cabot Library last week, Sarah L. Paiji ‘06 was standing at the Memorial Hall shuttle stop waiting for the 4:30 a.m. shuttle.

She stood alone as the whipping wind brought temperatures to -16 degrees. She waited from 4:20 a.m. until 4:36 a.m.. The shuttle never came.

Paiji had two words—“Very depressing.”

As in past years, Harvard Shuttle Services has instituted 24-hour service in effect from January 6th through 27th to serve students better during reading and exam periods, when libraries have extended hours.

But many students, hoping to take advantage of the service, have been disappointed by its inconsistency. “Shuttle services has a lot of great qualities; they also have some that need work,” said Nichele M. McClendon ’06. “This is one of them.”

With subzero temperatures and an increasing number of sexual assaults in Cambridge, students are particularly eager to take advantage of the shuttles. Drivers said they have noticed a definite increase in ridership.

“It’s a good idea, but it’s unreliable in practice,” McClendon said.

Paiji, who has been left waiting for late-night shuttles three times already this reading period, was less complimentary.

“The current service is a joke,” she said.

Paiji said she has been forced to take cabs and once resorted to spending a night sleeping in Cabot Library. “Drivers need to be adhering to the schedule regardless of the time of day or the number of riders,” she said.

The inconsistencies come at a time of heightened awareness about safety on Harvard’s campus. There have been five sexual assaults reported in the last four months in the Harvard area, the most recent of which occurred Saturday night in Harvard Yard.

“I was shocked to hear that shuttles just didn’t come,” said Bridget E. Deacon ’05. “I mean, if you’re not going to walk home by yourself anyway, what are you going to do?”

McClendon expresed similiar concerns.

“If I’m left standing at Johnston Gate late at night, it gets sketchy. The Square and the Yard don’t even feel that safe anymore.”

Paiji and several other concerned students have written directly to Shuttle Services.