Replacing traffic signals at-grade rail crossings and roadway junctions with roundabouts, for better operation, recovery, and safety.

Frank Penry

Senior Traffic Project Manager
GHD Inc.

Frank Penry is a licensed civil and traffic engineer, with over 25 years of experience in transportation planning and traffic engineering design. As Senior Project Engineer with GHD Inc., he has managed numerous transportation studies and design projects throughout California. Based out of Santa Rosa, Frank and his family reside in beautiful wine country, where he has served as the City Traffic Engineer for the City of Petaluma, as well as providing on-call services to many local communities. Frank’s experience includes a substantial time working with the permitting of at-grade rail crossings and coordination with traffic signal and rail interconnects.

Matt Wargula is a Senior Project Manager with GHD Inc. as well. He is licensed as a civil in multiple states and a traffic engineer in California, with over 19 years of professional experience. He is also located in the Santa Rosa, where he resides with his family. While also based in the Sonoma wine country, Matt has completed projects throughout California. His educational background is in civil engineering, and has prepared numerous planning, design project, including construction administration for a broad range of projects. Matt is engaged in the -project management and design of civil engineering infrastructure construction documents.

The presentation will provide findings of operational analysis, recovery benefits, and safety aspects of the installation of roundabouts at two Northern California sites, “Wine Country Roundabouts”. At each location, the authors will present the comparison of a 4 and 5 leg roadway junctions with center at-grade rail crossings, where traffic signal controls are replaced with single-lane roundabouts and standardized railroad safety equipment. In Healdsburg, a 5-legged roundabout design presented the community and businesses with an opportunity to reduce inherent delays associated with a complex phased traffic signal and railroad controls. The goal being to create economic opportunities, place making, and invite all mode users along the main corridor, a gateway to the thriving destination town. In Windsor, the 4-leg junction presents an opportunity to improve operations of a busy intersection and gateway to the Town Green, the heart of activity for this young community. The adjacent commercial and residential uses, along with a 1,800-student high school and a transit rail depot, make this intersection the hub of community activity. An extensive outreach program and intersection control analyses, with detailed analysis, modeling, and preliminary designs, highlighted the benefits of roundabouts at both locations despite the hefty construction costs compared to modifying traffic signal controls to meet the growing needs of the communities and at-grade rail crossings to meet current standards. While the intersections could not be relocated or grade separated to remove rail conflicts, the roundabout designs not only accommodated the central at-grade railroad, but provide more efficient operations with the rail activity and improved operations for all users.

A case study for the removal of traffic signal controls and modification of at-grade railroad safety equipment at 4 and 5 leg roundabouts with center island at-grade railroad crossings. The learning objective being to understand and consider how these installations simplify pre and post rail pre-emption activities, standardize active traffic control devices, and improve intersection recovery operations. The target audience being planners, designers, and public officials with at-grade crossings.

While the NCHRP guide discourages locating intersection near at-grade crossings, the nearly 200 year old rail system predates our modern roadway network and many of our western cities. In many cases, the railroad is not only unavoidable, but holds the principal right-of-way at grade crossings. Roundabouts have proven to be more effective that traffic signals in many instances, however concerns for their operation near or at rail grade crossings is enough to keep the benefit of an opportunity from realization.