The incident happened at around 4pm at Commerce and Milam. Authorities say the woman was driving down Commerce near Milam plowed straight through the guardrail and into the water.
"I was sitting on the bridge and I just see the car just drive over the edge of the bridge," one witness told us. "The car hit the water, the body flew out."
Several officers near the scene were able to pull the woman out of the water moments after the incident.
"When we crawled down the enbankment, we saw the lady floating in the bayou face down so we just went in there and grabbed her and started CPR on her, and we were able to revive her I think," Houston Police Department Officer Rene Caulderon said.
The woman was transported to Memorial Hermann Hospital. She is listed in critical condition.
And while it may have been all in a day's work for the officers, it was a scene eyewitnesses will never forget.
"An unexpected occurrence -- a car driving over the edge of a bridge. That, you don't see that every day. So you just feel for the person and hope they are all right," the witness said.
Investigators are still trying to determine what caused the accident.
Road crews put a temporary guardrail to replace the one through which the woman smashed.
