Gilberts Corner Roundabout Evaluation

KAI led a study to evaluate potential design modifications to address existing operational and safety concerns at the Gilberts Corner roundabout, located at the intersection of US 50 (John Mosby Highway/Lee Jackson Memorial Highway) and US 15 (Monroe-Madison Memorial Highway) in Loudoun County, Virginia.

The evaluation considered a broad range of possible factors contributing the observed frequency of crashes at the roundabout since it opened in 2009, including geometric design parameters (fastest path and design vehicle checks), turning movement volumes and distribution, capacity calibration using the new 2010 Highway Capacity Manual capacity model, sight distance, and pavement markings and signs.

Ultimately, KAI recommended a low-cost redesign to address geometric design issues and covert the hybrid multilane roundabout to a pure single-lane roundabout.