I tell you this as an introduction to the following true story and why it struck me as especially strange.
On my way home from work last night, going south on 99 just before the bridge, the car in front of me was swerving as well as slowing down and speeding up at random. I decided to pass it during one of the slow phases. I looked over as I passed to see what was going on with the driver.
It was a gaunt black man in his early 30s and he was driving with his elbows on the steering wheel. I suppose this is because his hands were full. In his right hand, he was holding a green glass bottle with no label that I could see. In his left, a red patterned handkerchief.
He was in the process of pouring liquid from the bottle onto the handkerchief. After he poured it, he held it up to his mouth and nose and breathed in with his eyes closed. I was mesmerized and lingered to watch the whole process. After a moment, his eyes opened wide and he was looking directly at me. I jammed on the gas and passed a few cars. He tried to follow me at first, but I don't think he was in any condition to give chase.
After about 30 seconds of trying to pass cars and reckless driving, I saw his car slow down and fall back into his previous swerving pattern.
I make no claims to know what he was sniffing or what was going on.