Police say they received reports of the man on the shoulder of I-880 waving the BB gun around 9:45 a.m. Armed officers quickly arrived at the scene and took the man into custody peacefully and without incident.
Officers say the BB gun looked identical to a handgun.
The suspect is being held on a psychiatric hold at a hospital for 72 hours.
All lanes of I-880 were briefly shut down by police, but have since reopened.
No injuries have been reported.
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