HOUSTON -

Toby Keith was rocking the house at the 2013 Houston Livestock Show & Rodeo and the midway bathed in bright lights when Yvonne Herndon and her husband Bob were catching a ride back to their car aboard one of the golf cart shuttle services operated by the rodeo.

That's when the plaintiffs in a lawsuit filed Monday claim the driver of that golf cart made a sharp left turn, which catapulted Yvonne out of the cart, head-first into the parking lot pavement.

Ever since that night six months ago, Yvonne, or Bonnie as she's known, has been lying helplessly in a coma, suffering from a severe closed head injury.

Now her family is suing the Houston Livestock Show & Rodeo, the driver of that golf cart and the golf cart company itself for an undisclosed amount of money.

HLSR CEO Leroy Shafer issued a statement which read in part:

"The petition involves a tragic accident that has deeply saddened and pained our organization. Bonnie is a member of our show family.  She is a longtime show volunteer, a member of the show's board of directors...Our thoughts have been, and will continue to be, with Bonnie and her family."

The case was just filed Monday; it will be months before it goes to trial.