3.2 Roundabouts, Traffic Circles & Special Intersections

3.2 Roundabouts, Traffic Circles & Special Intersections

Transportation agencies across North Carolina, including NCDOT, have increasingly constructed roundabouts and specialized reduced-conflict intersections to enhance traffic safety and reduce congestion. Understanding how to navigate these circular and non-traditional intersections correctly is essential for safe driving and performing well on the North Carolina DMV Driver Knowledge Test.

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Navigating Modern Roundabouts in North Carolina

A modern roundabout is a circular intersection where traffic flows counterclockwise around a central island without the use of traffic signals. Modern roundabouts are designed to reduce vehicle speeds and eliminate high-severity crash types, such as head-on collisions and broadside (T-bone) crashes.

Key Characteristics of Roundabouts

• Counterclockwise Flow: All traffic inside the roundabout travels in a single direction—counterclockwise (to the right of the central island).
• Yield-at-Entry Control: Every entry lane is controlled by a yield sign and yield pavement markings.
• Low Design Speeds: Roundabouts are engineered for low driving speeds, typically between 15 mph and 25 mph.

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Step-by-Step Procedure for Driving a Roundabout

1. Approaching the Roundabout

• Slow down as you approach the roundabout and obey all posted speed limit signs.
• Pay attention to lane selection signs and pavement markings well before reaching the intersection.
• Watch for pedestrians and bicyclists crossing the entry lanes and yield to them in marked crosswalks.

2. Entering the Roundabout

• Yield to Circulating Traffic: Drivers entering the roundabout MUST yield the right-of-way to vehicles coming from their left that are already circulating inside the roundabout.
• Wait for a safe, adequate gap in traffic before merging smoothly into the counterclockwise flow.
• If there are no vehicles inside the roundabout, you may enter without stopping.

3. Driving Inside the Roundabout

• Once inside the circular roadway, you have the right-of-way over entering vehicles.
• Do Not Stop: Keep moving counterclockwise until you reach your intended exit, unless stopping is necessary to avoid a crash or to yield to an emergency vehicle.
• Stay in Your Lane: Do not change lanes or overtake other moving vehicles while inside a roundabout.

4. Exiting the Roundabout

• As you approach your desired exit road, activate your right turn signal to inform drivers behind and entering the roundabout of your intent to exit.
• Maintain a safe speed while exiting and yield to any pedestrians crossing the exit roadway.
• If you accidentally miss your intended exit, simply continue driving around the central island a second time until you reach your exit safely.

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Multi-Lane Roundabouts

Multi-lane roundabouts feature two or more circulating lanes and require drivers to select the appropriate lane before entering the roundabout.

Lane Selection Rules

• Right Lane: Select the right lane if you plan to:
  • Turn right at the first exit.
  • Go straight through the roundabout (second exit).
• Left Lane: Select the left lane if you plan to:
  • Go straight through the roundabout (second exit).
  • Turn left (third exit).
  • Make a U-turn to head back in the direction from which you came.

Important Multi-Lane Safety Rules

• Never drive alongside large commercial trucks inside a multi-lane roundabout. Large trucks may require both lanes to navigate the central island radius.
• Never cut across lanes or attempt to turn right from the inside (left) lane.

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Modern Roundabouts vs. Old Traffic Circles (Rotaries)

Many drivers confuse modern roundabouts with older, large-diameter traffic circles or rotaries. It is crucial to understand the structural and operational differences for your DMV exam:

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North Carolina Superstreet Intersections (J-Turns / RCIs)

North Carolina has pioneered the use of Superstreet intersections, officially designated as Reduced Conflict Intersections (RCIs) or J-Turns.

How Superstreet Intersections Work

On high-speed multi-lane divided highways, traditional left turns from side streets account for a high number of severe T-bone collisions. Superstreet intersections redesign these crossings to eliminate direct left turns:

1. Drivers on the side street wishing to turn left or proceed straight across the main highway cannot drive directly across the median.
2. Instead, side-street drivers MUST turn right onto the main highway.
3. Drivers then move into the left lane and make a legal U-turn at a designated median crossover opening located downstream.
4. From the U-turn lane, drivers can complete their travel direction or proceed right onto the intersecting street.

Safety Benefits of Superstreets

By forcing side-street traffic to turn right first, Superstreet intersections eliminate over 60% of potential vehicle conflict points and reduce severe injury collisions on North Carolina highways by a large share.