The former Liverpool defender was working as a pundit during his former side's 2-1 Premier League defeat at Old Trafford.
Carragher was driving home after summarising on Manchester United's win over Liverpool at Old Trafford when he apparently became involved in a conversation with the occupants of an adjacent vehicle.
Spitting at someone is classed as common assault, punishable by a fine, community order or up to six months in prison.
Carragher's fellow Sky Sports pundit Gary Neville said this was an "isolated incident" and hoped the former Liverpool man would be able to continue in his role.
In the footage Mr Hughes" daughter can be heard saying: "He spat on me'.
Asked if he had seen the girl in the auto, he replied: "I didn't to be honest, she was leant back".
Police are understood to have spoken to Mr Hughes about filming on his phone while behind the wheel today.
Veteran Radio 2 presenter Jeremy Vine is among those to have weighed in on the issue, arguing the motorist should be sent to prison. Greater Manchester Police reportedly aren't likely to slap the usual £200 fine and six penalty points, and instead will offer "advice".
"I'll speak to the family again. People are saying "he should go to jail because he was driving like a lunatic" but the auto was basically stopped".
Carragher appeared on Sky News yesterday as the story was gathering momentum to plead for forgiveness.
He said: "I have no excuse".
"It is me biggest regret of course, but all I can do right now is apologise".
"There is no doubt what I have done is disgusting".
"It's just that moment of madness for four or five seconds".
Carragher was driving away after covering the game for Sky Sports when a United fan started goading him on the motorway.
"Jamie should have been to Old Trafford for us tomorrow night", TV3's head of sport Peter Norrelund told Danish media.
"He seems contrite. Everyone makes mistakes, we are all human".
"Sky takes this matter extremely seriously and strongly condemns Jamie's actions", Sky Sports said in a statement.