RALEIGH — Workers will use plastic and paint Friday night to simplify the eccentric roundabout at the N.C. State University Bell Tower, reducing it from two lanes to one.

Traffic on Hillsborough Street and Pullen Road will be detoured starting at 8:30 p.m. Friday. Jed Niffenegger, Raleigh’s senior transportation engineer, said he hopes to reopen the remodeled roundabout by 6 a.m. Saturday.

Police have logged more than 100 crashes since the roundabout opened in the summer of 2010. Most accidents happened when eastbound drivers on Hillsborough failed to give way to drivers in the roundabout. Many drivers said they were confused by the twin rings.

“What we’re doing should significantly reduce the crashes that continue to occur,” Niffenegger said. “I think for anyone that’s not familiar with it, it will be a lot easier for them to negotiate because there will only be one lane in the center.”

It is Raleigh’s only two-ring roundabout, and the only one where drivers have racked up lots of accidents. Traffic engineers realized some drivers would have trouble, so they published an illustrated navigation guide before the roundabout opened as part of a $9.9 million makeover of eight blocks of Hillsborough Street.

Over the past two years they made extra efforts to explain the roundabout to NCSU students; police records do not show large numbers of students involved in crashes.

Some street designers favored a single ring when planning began in the late 1990s, but city officials insisted on two rings to handle an expected growth in traffic. Traffic counts have fallen on Hillsborough Street since 2010.

Workers will apply raised domes called “Bott dots” to the pavement, along with white and yellow stripes of paint, to keep drivers out of the roundabout’s outer lane.

A slight curve will be built into the approach on eastbound Hillsborough, so drivers meet the circle more nearly at a right angle. Engineers say that should give drivers a better view of traffic in the roundabout.

The change also will erase the outer lane of westbound Hillsborough between Oberlin and Pullen roads. Drivers will still have two lanes as they enter the roundabout from the other three approaches, but the outer lanes will be marked for right turns only.

Siceloff: 919-829-4527 or blogs.newsobserver.com/crosstown or twitter.com/Road_Worrier/