The alleged Flinders St driver has reportedly been charged over the attack.
The alleged driver, Saeed Noori, is expected to face the Melbourne Magistrates Court shortly.
Police say he has been charged with 18 counts of attempted murder and one count of conduct endangering life.
The Heidelberg West resident was discharged from hospital on Friday and remained in custody, and was questioned by police on Saturday.
12 people are still in hospital as a result of the attack, with three people fighting for their lives.
Assistant commissioner Stephen Leane had previously said investigators were seeking advice on charges.
"I've got a firm belief that what he did on Thursday night was a deliberate act," he told reporters on Saturday.
"The motivations for that act, we'll work through.
"Our investigators will charge him with appropriate offences, if that's what's going to happen today."