The R Street extension across Fahrens Creek in the City of Merced is a dual purpose structure.  The two-cell reinforced concrete box culvert carries the creek flow, while a separate tunnel was created to carry pedestrian and bike traffic safely under R Street.  The culvert is approximately 120 feet in length and follows the geometric curve of the existing creek.  Cornerstone designed the culvert with warped wingwalls at both the entrance and exit of the culvert to minimize hydraulic losses, and called for rock slope protection similar to the adjacent existing structure.  The paved and lighted bike tunnel, separated from the creek by an earth berm, is 12 feet wide  and 8 feet tall, and travels under R Street for a distance of 160 feet.