The incident began Tuesday morning when the driver of a white pickup truck suddenly stopped in busy traffic on the southbound 215 in Perris.
An alert trucker stopped other drivers and then called 911, fearing the pickup's driver was having a medical emergency.
But when a CHP officer arrived and approached the pickup, eyewitnesses say the driver was taking off articles of clothing and acting erratically.
The video shows him charging at the officer and shouting incoherently.
That's when the officer deployed his Taser, sending the twitching man to the ground. But even that didn't calm him down. He continued to thrash and mutter as the officer tried to get him under control.
That's when several of the other drivers who had stopped on the freeway moved in to help the solo officer subdue and handcuff the man.
No word yet on whether the man was under the influence of any controlled substance.
The CHP took the man into custody and got traffic moving again.