Pedestrian crossings in several areas of northern California have been hacked with fake greetings mocking the tech billionaires Elon Musk and Mark Zuckerberg.

Officials in Silicon Valley are investigating and have disabled the audio feature on the crossings which usually plays instructions to “walk” or “wait”.

The surprise message were noticed over the weekend in Palo Alto, Redwood City and Menlo Park – which is home to Zuckerberg’s sprawling Meta campus.

One Musk impersonation offered to buy passing pedestrians a Tesla Cybertruck if they agreed to be his friend. Another from a false Zuckerberg said “real ones call me The Zuck”.

It is still unclear who created the messages or how they ended up being played from the crossings.

Officials in the affected areas, which are all just south of San Francisco, told the BBC engineers were investigating how the crossings were tampered with.

Pedro Quintana, a spokesman for the California Department of Transportation (Caltrans), said about 10 pedestrian crossings within the Menlo Park and Palo Alto areas had been impacted.

All of those are now working on a timer system and the buttons which launched the fake messages have been deactivated, he said.

The messages appeared across Silicon Valley, where both tech billionaires have business.

One of the fake messages in Musk’s voice welcomes people to Palo Alto, which is home to Telsa operations.

“You know, they say money can’t buy happiness and… I guess that’s true. God knows I’ve tried,” the message says in one video shared multiple times on social media.

One from a fake Zuckerberg starts with him introducing himself before discussing inserting AI “into every facet of your conscious experience”.

Neither man has commented on the incident.

The city of Palo Alto separately told the BBC that at least 12 crossings in the downtown area had been tampered with.

Meghan Horrigan-Taylor, a spokeswoman for the city, said another city employee alerted officials to the issue on Saturday when they noticed the voice feature was not functioning properly. She added officials believe the tampering may have occurred on Friday.

“City staff have disabled the audible feature until further repairs can be made,” she said. “Other traffic signals in the city were checked and the impact is isolated.”

Local media also reported that several crossings in the Redwood City area were also hacked to sound like the two billionaires.