Judges at the European Court of Human Rights are considering a test case after two UK drivers challenged a ruling over speed cameras.
The motorists claim existing laws affect the right to a fair trial
Currently, the owners of vehicles caught speeding on camera are obliged to declare who was driving at the time.
The drivers say this breaches their right to silence. Following a hearing, judges are considering a ruling that could impact on millions of UK drivers.
Transport Minister Stephen Ladyman said he believed the government would win.
Motoring campaigners are divided over the case but ministers have said they would "vigorously" defend current laws.
Idris Francis was issued with a penalty notice after his car was caught on camera breaking a speed limit in June 2001.
The 66-year-old from Hampshire refused to reveal who was at the wheel at the time, so was fined for failing to sign a speeding notice.
In April 2000, a car belonging to Gerard O'Halloran, 72, from London, was caught by a speed camera.
He initially admitted the offence but later tried to withdraw his admission, claiming he signed the statement only because he feared he would be punished if he did not.
The pair appealed to British courts but were turned down. They eventually decided to take their cases to the European courts.
Mr Ladyman, told BBC News he was confident the government would win the case.
"It is not a form of duress," he added.
"If you were speeding you can pay a small penalty and have three points on your licence as an alternative to going through the hassle of going to court and potentially a much bigger fine and a much bigger penalty," he said.
"The fact the alternative of going to a court is there means there are no human rights being undermined here, there are no long-standing liberties being undermined."
Liberty's legal director James Welch said vehicle owners had two choices when presented with a speeding notice - to name the driver, or to refuse to provide information - both of which carried similar penalties.
Idris Francis was "disappointed" after UK courts rejected his appeal
"This offends against a very important principle - namely that you should not have to incriminate yourself," he said.
"You should not be made subject to a criminal penalty in order to make you provide information that then forms part of the prosecution case against you."
Mr Welch said the issue was less important in cases involving more serious charges - such as death by dangerous driving - because speed camera evidence would rarely be used.
He said that, if the case was successful, the government would have to find new ways of collecting evidence in speeding cases.
The Department for Transport said the case concerned "the requirement for vehicle keepers to identify the driver of a vehicle identified on a speed camera".
"The applicants claim this requirement breaches the right against self-incrimination and thereby their right to a fair trial under the European Convention on Human Rights.
"The UK government does not accept this claim."
The case renews the debate about speed cameras, with campaigners on either side joining the argument over the case.
Paul Smith from Safe Speed, who believes cameras divert motorists' attention away from the roads, said British justice had been "undermined for the sake of nothing more than needless mass prosecutions".
Jools Townsend from the Brake charity, who supports speed cameras, said if the pair won their case it would have a "devastating effect" on road safety in the country.
The court's ruling on section 172 of the Road Traffic Offenders Act 1988 is not expected for several months.