Smith was arrested and Locke was a passenger in the accident, which took place in Hull in September.
Smith was banned for driving for 28 months and fined £600 for careless driving and £900 after failing to provide a specimen after the crash.
The halfback was later sacked by the Wildcats and has since returned to Australia and is believed to have now retired.
Locke was also released by the club and is attempting to return to the NRL after a troubled short spell at Wakefield.
Salford owner Marwan Koukash tweeted: “This is terrible and hope they have learned their lesson. Both still have a lot to offer.”
The Wildcats were being approached for comment.