The rule was stated in the insurance policy the production company of "Liz & Dick" took out, reported Ace Showbiz.
It would take a major hit if the TV movie could not be completed. So, the no-driving rule was set for the 25-year-old actress to avoid her from getting any trouble that could affect the filming.
The production honchos reportedly knew that Lohan was driving, but post the Porche accident, they made it clear that she would not drive again until the movie gets finished.