Yeah major differences between the movie and what happened. 

Film characters Lou Jean Poplin and Clovis Michael Poplin are based on the lives of Ila Fae Holiday and Robert Dent, respectively. The character Patrolman Slide is based on Trooper J. Kenneth Crone.
In real life, Ila Fae Holiday did not break Robert Dent out of prison. Dent had been released from prison two weeks before the slow-motion car chase began. (wikipedia)

In fact the movie seems to go out of its way to blame most of this on Lou Jean, she can’t get custody of her child back, barely understands the procedure how to so she goes to the Pre-Release facility where her husband is at, and he’s got 4 months on a 1-year sentence and manipulates him and nearly drags him out of there despite his protestations (she wears two sets of clothes so he can wear one. 

In reality Robert Dent had been pulled over for a routine traffic stop but did not know why. He panicked and drove off.

In the movie, they hitched a ride with an old couple who drive painfully slow and are pulled over because of the driving. The couple is out talking to the patrolman when Lou Jean panics and she drives off. 

In real life they aren’t chase by Crone but make it to the woods and hide their vehicle there. They call the cops from a ranch house posing as hitch hikers that have been beaten and robbed. That’s when Crone enters the scene. He’s beaten and disarmed and taken captive. They take him to his cruiser and just tell him to drive.

They really didn’t have any plan. They kidnapped the patrolman, same as in the movie, but it’s not until some time that they demand to go see his stepkids, her kids at her mom’s house…in Wheelock. The whole thing does last a few hours (rather than a couple of days) and involves over  hundred vehicles and goes from Port Arthur to Houston to Navasota and finally Wheelock.

In the movie they crash their car with Officer Slide in pursuit. Clovis is dazed and Lou Jean fakes being hurt so she can get close enough to slide, grab his gun and *tosses it* to Dent. She puts him in the position again of escalating things. it takes him a few moments and he’s slower than Slide to go for the gun but he reaches it first.

The end result is the same, but all three walk up to the house and Dent is shot and killed when he opens the door (rather than a sniper bullet). 

Whether Crone gave his tacit approval for this film I don’t know but he did serve as a technical advisor and played a small part in it as a deputy.

And Ila Fae Holiday? She served 5 months on a 5 year sentence (rather than 15 months as the movie states) and apparently died of natural causes in 1992 working at a motel in Livingston (although what are natural causes at 44 y.o.?)

hold your butter pardner.