Witnesses told a judge they saw Alexandria Duval fighting with her twin and business partner Anastasia while driving in Maui in 2016.
Prosecutors alleged that Alexandria then intentionally rammed her SUV into a wall before plunging 200 feet over a cliff.
Alexandria was pulled to safety. Her sister died in the passenger seat.
The defense maintained it was an accident.
Alexandria's attorney said she's going to take the time to figure out what to do next now that she's been acquitted.