For those who tried to help the man, they say it was very hard to watch.
Eyewitness Alida Carrier recalled, "I was telling him to roll down his window and try to get him to crawl out, at least, as the truck was going under water. He was shaking his head no. He locked the doors and just sat there and went completely under water."
"You wanted to do something, but you couldn't. The people over there wouldn't let us get in the water," said eyewitness Greg Hinojosa. "We were going to dive in and get after him, but, you know, you could probably die, too. I don't know what would trigger somebody to do something like that. It's terrible."
The driver was reportedly a white male in his 30s or 40s. He was believed to be alone in the pickup. The man's body will be taken to the Harris County Medical Examiner's Office for an autopsy to determine the cause of death.
This is being treated as a crime scene until it officially determined an accident or suicide. The ferry will resume operations Thursday morning.