Artist’s overview of the roundabout at the junction of Routes 50 and 15 in Gilbert’s Corner, which will be modified. (VDOT)

A roundabout, the modern version of a traffic circle, is better at moving vehicles than a traditional intersection with a traffic signal — as long as drivers follow the rules about speeds and right of way.

What are the odds? Apparently, they weren’t good enough at the junction of two major routes in Loudoun County, where the Virginia Department of Transportation installed a roundabout four years ago. Drivers are going too fast and there are too many crashes, VDOT said.

By Thanksgiving, VDOT plans to make $300,000 worth of modifications to the roundabout where Routes 50 and 15 intersect in Gilbert’s Corner. Crews will adjust the curb lines, pavement markings and signs so drivers will have a single lane on all approaches to the roundabout. Now, there are two lanes along the north-south Route 15 approaches. VDOT officials hope this will reduce speeds and driver confusion in the roundabout. They said a traffic study showed the roundabout could handle this traffic pattern with only a slight delay at peak periods.

The reconfiguration is going to increase the curvature leading into the roundabout, which VDOT expects will slow down drivers while at the same time making the roundabout easier to navigate.

VDOT engineer Jim Zeller said in a statement that the roundabout has exceeded expectations on traffic flow, “but there has been a major downside. Some motorists are simply driving too fast, which has led to many crashes.”

There were 11 crashes at the intersection in 2007, the year before the roundabout was installed. In 2010, there were 36 crashes, 31 in 2011 and 30 in 2012.

The speed limit entering the roundabout is 25 mph. Even drivers who want to speed can’t go really fast entering the roundabout so the collisions tend to be less damaging than those on a straight-away. Still, VDOT said, an average of five crashes per year involve injuries.

VDOT is hosting a meeting for the public to see the plans on Tuesday from 7 p.m. to 9 p.m. at Aldie Elementary School, 23269 Meetinghouse La., Aldie.