JOHANNESBURG — A politically influential son of former President Jacob Zuma of South Africa was cleared of culpable homicide on Friday in a case that has come to be seen as a proxy for factional battles within the governing African National Congress.

The charges against the son, Duduzane Zuma, also included negligent and reckless driving in connection with a crash in February 2014, when his sports car — a Porsche 911 Turbo — hit a minibus in Johannesburg. One minibus passenger died, and several other people were injured.

Delivering his judgment in a Johannesburg courtroom, Magistrate Tebogo Thupaatlase said that the state had failed to prove Mr. Zuma’s guilt in the trial.

Defense lawyers contended that there was no evidence of negligent driving by Mr. Zuma and said the Porsche had hydroplaned on a puddle, an outcome they argued was beyond the driver’s control. The judge seemed to agree, saying of the puddle that “a reasonable driver would not have been able to see it.”