The Harris County Sheriff's Office says the driver of the vehicle that struck the woman stayed at the scene and is cooperating with authorities.
Police are working to determine if the driver was impaired in any way.
They are unsure why the woman was trying to cross the freeway.
Authorities warn that it is very dangerous to cross such a busy freeway, especially in the dark.
They advise pedestrians don't try to cross the freeway unless they're at a crosswalk.
All of the eastbound lanes of I-10 were closed for about four hours.