Unless they get rained out, workers for the city of Raleigh will close the eccentric, crash-prone roundabout on Hillsborough Street tonight for a redesign. When it reopens Saturday morning, it will be reduced from two lanes to a single lane.

Traffic on Hillsborough Street and Pullen Road will be detoured starting at 8:30 p.m. 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.

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.