Going over the RFK bridge westbound this truck seeeved into my lane as I was passing coming within inches of scraping the side of my car nearly crushing me between his truck and the bridge railing! I needed to be in the right lane for where I was headed. He was in the middle but needed to get over to the left to go where he was headed. Why he drifted into the right lane as I was halfway past him is beyond me. When I got past him I seen him looking straight ahead in awe taking in the city view and holding a drink cup to his mouth!