A pickup truck hit a boulder and tumbled over a 150-foot cliff, but the 71-year-old driver survived with relatively minor injuries, officials said.
"It was a miracle that someone saw her vehicle," sheriff's spokesman Rick Glancey said. "It is one of these days when God was on her side."
Helene Crosser told authorities that she was driving on Loop 375 to watch the sunrise early Sunday when her shoe fell off and got jammed beneath the brake pedal.
Crosser said she tried to pull off the road but couldn't slow down because the shoe stopped the brake from fully working.
She was trapped in the Texas heat for seven hours until a driver spotted a glint of light reflecting from afar and called 911. Authorities said Crosser didn't have a cell phone with her.
Crosser was taken to a hospital with dehydration and non-life-threatening injuries.