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Ravensworth Road intersection of Fountain Head Dr – Jayhawk St
The Federal Highway Administration (FHWA) recently began a pilot program to examine anew modular approach to construct mini roundabouts that use prefabricated materials, like raised islands made from engineered plastic developed from recycled plastic bottles, which will allow for ease of installation at a lower cost.
Wei Zhang, of FHWA, recently commented: “if the materials and design are successful, we may be able to consider similar modular roundabouts as an option where safety and congestion improvements are needed quickly.”
MTJ Roundabout Engineering, in conjunction with ZKxKZ, LLC of Lexington, MA, provided design support for the latest mini roundabout in this initiative located in Annandale, VA.
The previous intersection was dangerous for traffic entering from side streets, for making left turns, and particularly hazardous for pedestrians. The design and review of colors and specifications provided by MTJ were instrumental in creating a safer environment for all modes while preserving the capacity of the intersection. The Virginia Department of Transportation (VDOT) reported that this project required no new pavement, utility relocations, drainage, or other work which kept costs significantly lower than other alternatives.
To learn more about the project, or see a video, please use the following links:
For other questions, please contact leaders on the project team:
Mark Johnson, PE
MTJ Roundabout Engineering
Wei Zhang, PhD, PE
Terry Yates, PE
Editors at the Monterey County Weekly have named the Holman Highway 68 roundabout as their county’s “Best Use of Government Funds” in 2017.
The locally owned Seaside, California-based newspaper featured the project in its “Best of Monterey County” annual issue, which was published on March 22, 2018.
The roundabout, which replaced a congested intersection and serves as primary access to Pebble Beach and Community Hospital, has “radically improved the quality of the commute life for thousands of travelers,” the paper said.
Congratulations to all our partners who worked on this exciting, challenging project.
Mark T. Johnson and Ting-Li Lin’s (Ph.D., Statistics) paper, “The Impact of Geometric Factors on the Capacity of Single-Lane Roundabouts,” received the TRB Roundabout Committee’s Best Paper Award, presented at the 2018 TRB Annual Meeting in Washington, DC. The paper will be published in the 2018 Transportation Research Record (TRR), Journal of the Transportation Research Board.
The paper compared two methods of capacity estimation on US Data — HCM6 gap-acceptance and Kimber’s geometric model. Our statistical analysis showed that the geometric model was more accurate, and produced better predictions than HCM6 model. See the full paper here and watch the paper presentation below.
Mark Johnson, PE will be giving three presentations at the 2018 TRB Annual Meeting in Washington, DC.
Jan. 9, 10:15am – 3:15pm – Roundabout Video Theater
1) Morning session: Video presentation – “Roundabout Design & Traffic Planning for All Modes”
2) Afternoon session: Case Study presentation – “Innovative Pedestrian/Bike Design Treatments in an Urban Compact Roundabout”
Jan. 9, 3:45pm – 5:30pm – Podium Presentation
3) Mark will present his paper, “The Impact of Geometric Factors on the Capacity of Single-Lane Roundabouts,” which was accepted for publication.
Co-authored with Ting-Li Lin, Ph.D., the paper compared two methods of capacity estimation – HCM gap acceptance and Kimber/Hollis’ geometric model. Our statistical analysis indicated that the geometric capacity model was more accurate. The uncalibrated geometric capacity model produced better predictions than the calibrated HCM6 model. This paper concluded that the accuracy of capacity prediction is improved by including geometric variation, and the geometric differences between roundabout sites were the primary cause of the differences in driver behavior at those sites.
Not every roundabout gets its own cookie!
The grand opening celebration of the Holman Highway 68/Highway 1 Roundabout in Monterey, CA included this cookie, and a bumper sticker.
Mark Johnson, PE will be presenting at the Ohio Transportation Engineering Conference in Columbus, OH. His presentation “Too Many Crashes at Your Multi-Lane Roundabouts? Learn How to Optimize Safety for Multi-Lane Roundabouts” will be on Oct. 11 at 8am.
Session 49 – More About Roundabouts
Multi-lane roundabouts are having excessive PDO or minor crashes, which is creating many challenges for implementation. This presentation details the essential components for designing optimal roundabout safety and operations, and highlights how these elements blend together that affects how drivers process that information and then react to it.
See you there at this topical presentation!
Mark Johnson will be presenting at the TRB webinar “Modern Roundabouts: Downtown and Suburban Revitalization.”
The webinar will be on Monday, September 18, 2017, from 2:00 PM to 4:00 PM ET and will provide examples of ways the modern roundabout may be able to revitalize a downtown area, enhance a community’s sense of place, and provide a safer and more efficient traffic flow in urban and suburban areas. Presenters will describe how roundabouts have jumpstarted downtown revitalization, illustrate how roundabouts have enhanced communities, and demonstrate how roundabouts have improved traffic flow.
Two PDH credits are available. For more information or to register see TRB’s webinar page.
Mark Johnson is presenting a training for the Ohio DOT LTAP: 2017 Ohio Roundabouts Conference in Hilliard, OH on Friday, Sept. 15th. His training will cover the trending topic “Designing Roundabouts for Multi-Modal Safety.” A tour of Hilliard, OH roundabouts will be included in the one-day conference.
This is the first roundabout planned along a corridor of nine roundabouts on Park Avenue (SH 9). MTJ Roundabout Engineering worked with the Town of Breckenridge, CO and McDowell Engineering on the peer review for this project.