Tunnel is named after late Comedian Robin Williams

According to SFGate, the signs -- one on each side of the tunnel -- were installed by Caltrans on February 29. The installation occurred several months after the California state legislature approved a bill to change the tunnel's name in honor of late actor/comedian Robin Williams.

Previously, the structure was unofficially known as the Waldo Tunnel or the Rainbow Tunnel.

"Robin Williams was a friend to the North Bay community of the San Francisco Bay area," the bill read. "He would often drop in unannounced at comedy nights at the 142 Throckmorton Theatre in Mill Valley. There he would encourage young, budding comedians. He did so with kindness and humility and many comedians aspired to perform with the same level of wit and insight as Robin Williams."

Williams, who died in August 2014, was a long-time resident of Marin County. Last year, a woman named Julie Wainwright started a Change.org petition to rename the tunnel as a tribute to him. 

"He was my neighbor -- I often saw him running errands, walking the dog, performing at the local theater, working at the coffee shop," Wainwright wrote on the campaign page. "Robin wasn’t just an international icon -- he was an integral part of our community here in the Bay Area. We claim him as our own."

According to The Associated Press, the signs cost $3,000, and were paid for with private donations.