Shuttles will now run between the Quad and River Houses all night, providing students with 24-hour transportation for a one-month trial period.

The extended shuttle service, which started last night, comes after a series of sexual assaults on or near campus. But Assistant Dean of the College Paul J. McLoughlin II said the incidents did not spur the change.

“This is not a reactive service, but the assaults did raise the issue of safety,” McLoughlin said.

The new 24-hour schedule is a trial to determine whether the service will be used by members of the Harvard community between 3 a.m. and 7 a.m. during the term, Dean of the College Benedict H. Gross ’71 wrote in an e-mail.

Buses will now run until 3 a.m., which is two and a half hours later than before. Vans will continue along the bus routes until the buses resume service at 7 a.m. Vans will also run during breaks scheduled for bus drivers.

During the extended hours, a shuttle will stop at each station every 30 minutes. The stops on the extended overnight route are Memorial Hall, Lamont Library, Winthrop House, Mather House, Johnston Gate, Currier House and Garden Street, said Carl A. Tempesta, operations manager for passenger transport and fleet management services.

Drivers will monitor the number of students who board the shuttle at each stop during the extended hours to determine whether the service should be continued, Tempesta said.

“We’re not necessarily going to go back to what it was before if only a few students ride the shuttle at 5 a.m. If there are unproductive hours the [Harvard University Police Department] will pick up the riders when the shuttle doesn’t operate,” said McLoughlin, who sits on a committee of students and administrators that examines safety on campus.

During reading period, the shuttle operated on a 24-hour schedule, but drivers were not monitoring passenger numbers. This month marks the first time the shuttle will operate 24 hours a day during regular classes.

Several students complained during reading period that shuttles stranded them late at night, and Tempesta said he hopes students will no longer find themselves without University-provided transportation options. After 3 a.m., he said, a central dispatcher will coordinate the shuttle buses, the evening transportation vans and the escort service. In the past, nocturnal students’ calls were met with a recorded message.

McLoughlin said Operations Services attributed the strandings to union-mandated breaks for drivers, and to discrepancies between students’ watches and the bus clocks.

“The transportation service has placed a clock online so students can synchronize their watches,” McLoughlin said.

A new student escort service will also begin this month to replace the now-defunct SafetyWalk. The program may begin the hiring process as early as tomorrow or Friday, McLoughlin said.

Three pairs of students, one of each gender, will work for the escort service each night, stationed in the Quad, the Yard and the River Houses. The escorts will wear clearly marked Harvard University Police Department (HUPD) vests and receive training, McLoughlin said. Each escort will also be in constant contact with HUPD and the transportation dispatcher.

Students responded positively to the announcement of the added service.

“I’m going to use [the extended hours of the shuttle] a lot. There are many times when I have been forced to walk,” Pforzheimer House resident Jane Y. Kim ’05 said.

“Even if only a handful of students are using the shuttle at 4 a.m., that makes it worth running,” incoming Undergraduate Council President Matthew W. Mahan ’05 said.

—Staff writer Joshua P. Rogers can be reached at jprogers@fas.harvard.edu.