The appeal courts all ruled that the four accused should face new trials after being acquitted under the so-called Carter defence, which allowed an accused to present evidence of alcohol consumption that could challenge a breathalyzer reading.
The four were charged before the federal government killed that defence in July 2008 with amendments to the Criminal Code.
Their lawyers argued that the amendments could not be applied retroactively and that the original acquittals should be upheld.
In a ruling earlier this month, the Supreme Court restored a drunk-driving acquittal against a man who used the Carter defence in a case that began before the law was changed, ruling that retroactive application of the new rules breached his rights.
In an unusual move Thursday, the Supreme Court referred the four new cases back to the appeal courts and ordered them to resolve the matters in accordance with this ruling.
A spokeswoman for Justice Minister Rob Nicholson said the department is continuing its review of the Supreme Court's fine-tuning of the impaired driving law.
"Our government takes the issue of impaired driving very seriously," said spokeswoman Julie DiMambro.
Nicholson has said the amendments introduced three years ago were to ensure "only scientifically valid defences" could be used as evidence to challenge a roadside breathalyzer test.
Under the amendments, defendants challenging a reading higher than the legal blood-alcohol content limit of 0.08 have to show the breathalyzer malfunctioned or was misused.Suggest a correction