KOA provided civil and traffic engineering services to the City of Calabasas for the Mulholland Drive Gap Closure project. The project included grading, drainage, road widening, new sidewalks, and retaining walls along Mulholland Highway and Old Topanga Canyon Road fronting Calabasas High School in the City of Calabasas. The project goal was to provide connectivity and a safe path of travel for pedestrians and cyclists within the project limits. A challenging aspect was a tiered retaining wall design along Old Topanga Road.