Edwin Jaykumar Samuel, 38, admitted to punching Peh Boon Hoe, 58, twice on the face along Jurong East Street 21 on July 31, 2011.
Peh was driving his company lorry in the Jurong industrial region and made a left turn, when Samuel also made the turn into the same road from the opposite direction at a fast speed while honking, the court heard.
Samuel has decided to appeal against the sentence. He was allowed a bail of Singapore dollars 15,000.
Singapore does not tolerate rage driving and exchange of abuse or fights in the flow of traffic.