National Roundabouts Week

4-Minute Read

To celebrate National Roundabouts Week, we’re featuring J2 public roadways roundabout projects that are currently underway and a fun drive through local Loudoun County roundabouts.

Wayside Drive Connector for the Route 234/Route 1 VDOT Park & Ride Expansion – Prince William County, VA

national roundabouts week
The roundabout along the proposed Wayside Drive Connector provides motorists access to the proposed expansion to the parking facility. The roundabout design accommodates full bus movements to service the relocated bus pickup/drop-off facility that is a part of the project expansion. The Wayside Drive Connector is part of the proposed “Quadrant Intersections” improvements connecting Route 1 and Route 234 in Prince William County, Virginia.

Route 15 North Widening, Battlefield Parkway to Montresor Road – Leesburg, VA
national roundabouts weekThe Loudoun County Department of Transportation and Capital Infrastructure is proposing improvements to US Route 15 from Battlefield Parkway to Montresor Road to address numerous safety concerns along the corridor and alleviate traffic congestion. Improvements include roadway widening from two lanes to four lanes, modification of the Leesburg Bypass Green-T Intersection, modification of the Whites Ferry/Raspberry Drive intersection, a proposed roundabout at the Montressor Road/Limestone School Road intersection, and a regional trail/shared-use path along the west side of US Route 15. The design includes two high-speed approaches for Route 15 legs. It will also include numerous landscaping features developed to support the Journey Through Hallowed Ground (JTHG) preservation of the corridor.

  • J2 Team Members: Jim Bishoff, Lorainne Barksdale, Jon Wilfong, Krizia Ortega, Carlos Ayala, Jamie Conard, Zoe Foxhall, Alexa Adkins, Wesley Michaelson, and Sean Hoffman
  • Client: Loudoun County DTCI
  • Teaming Partners: Supported by firms from varying Loudoun County DTCI On-Call Contracts
    • J2 – Roadway, Hydraulics, MOT
    • Rice – Survey & Plats
    • Michael Baker – Traffic Analysis, Signal Design, Signing & Marking
    • Dewberry – Structures, Lighting & Noise Analysis
    • Gordon/WSSI – Environmental Permitting
    • ECS – Geotechnical & Geophysical Investigations & Reporting
    • CES – Utility Coordination

Route 55 Roundabout – Just North of I-66 at the Intersection of Free State Road, Route 55, and Cunningham Farms Drive in Marshall, VA

national roundabouts week
The proposed roundabout is just north of I-66 at the intersection of Free State Road and Route 55 in Marshall, Virginia. The location is ideal for facilitating access to the proposed VDOT Park and Ride and the existing roadway network. The roundabout will provide traffic calming for entering the Town of Marshall and provide a pedestrian-friendly environment for the existing communities adjacent to the intersection.

  • J2 Team Members: Carlos Ayala, Krizia Ortega, Zoe Foxhall, Alexa Adkins, Jamie Conard, Jon Wilfong
  • Client: Van Metre Homes
  • Teaming Partners: Gorove Slade

Waxpool Roundabout – Waxpool Road & Faulkner Parkway Roundabout – Loudoun County, VA
national roundabouts weekThis 3-leg, multi-lane roundabout is being developed as part of the proffered agreement with the new Waxpool Crossing development. It has been designed for the ultimate 2043 traffic volumes, and it will be constructed to address the needs of the interim 2023 traffic volumes. Improvements include maintaining safe pedestrian access through the roundabout for neighboring parcels and ensuring the roundabout can be constructed with limited interruption to the current intersection operations.

The Waxpool Roundabout is a non-standard 3-leg roundabout that includes two high-speed approaches. The skew of the existing intersection with the need to avoid existing utilities, minimize impacts to neighboring parcels, and balance safe traveling speeds through the roundabout proved for interesting concept development.

What Exactly is a Roundabout?
According to the Virginia Department of Transportation (VDOT), a roundabout is a circular, unsignalized intersection where all traffic moves counterclockwise around a central island. Traffic entering the roundabout slows down and yields to traffic already inside the roundabout. Roundabouts can be designed with one or more circulating lanes. Design options allow for right turns to be channelized to bypass the circulating lanes.

Roundabout History
The Maryland Department of Transportation states,

Traffic circles have been part of the transportation system in the United States since 1905, when Columbus Circle, designed by William Phelps Eno, opened in New York City. Subsequently, many large circles or rotaries were built in the United States. The prevailing designs enabled high-speed merging and weaving of vehicles. Priority was given to entering vehicles, facilitating high-speed entries. High crash experience and congestion in the circles led to rotaries falling out of favor in America after the mid-1950s. Internationally, the experience with traffic circles was equally negative, with many countries experiencing circles that locked up as traffic volumes increased. …

The modern roundabout was developed in the United Kingdom to rectify problems associated with these traffic circles. In 1966, the United Kingdom adopted a mandatory “give-way” rule at all circular intersections, which required entering traffic to give way, or yield, to circulating traffic. This rule prevented circular intersections from locking up by forbidding vehicles to enter the intersection until there were gaps in circulating traffic. In addition, smaller circular intersections were proposed that required adequate horizontal curvature of vehicle paths to achieve slower entry and circulating speeds. …

(Modern roundabout) changes improved the safety characteristics of the circular intersections by reducing the number and particularly the severity of collisions. Thus, the resultant modern roundabout is significantly different from the older traffic circle both in how it operates and in how it is designed. The modern roundabout is a substantial improvement, in terms of operations and safety, when compared with older rotaries and traffic circles. Therefore, many countries have adopted them as a common intersection form and some have developed extensive design guides and methods to evaluate the operational performance of modern roundabouts.

When Should Roundabouts be Considered?
At intersections:

  • With heavy left-turn traffic or with similar traffic volumes on each leg
  • With crashes involving conflicting through and left-turn vehicles
  • With limited room for storing vehicles
  • Where there are limited nearby driveways

Benefits to Implementing Roundabouts

  • Improved safety: Reduces the number of points where vehicles can cross paths and eliminates the potential for right-angle and head-on crashes.
  • Increased efficiency: Yield-controlled design means fewer stops, fewer delays and shorter queues
  • Safer speeds: Promotes lower vehicle speeds, giving drivers more time to react
  • Long-term cost-effectiveness: No traffic signals mean lower long-term costs for operations and maintenance
  • Aesthetics: Allows for landscaping and beautification

*Source Virginia Department of Transportation (VDOT)

Finally, take a spin with us through several Loudoun County roundabouts to learn a few fun facts on why roundabouts are great.

To learn more about J2 Engineers and our transportation experience, visit our Transportation Services page or email info@j2engineers.com.