The Australian government is coming down hard on using cannabis and driving, with on the spot fines of $400 for a first offence.
This comprehensive report by the US Department of Transportation states that cannabis is relatively safe to drive on, so why the hefty fines? why any fine?

"The existing epidemiological research (both
culpability and case-control studies) have produced contradictory
estimates of risk for marijuana use. Some of
these studies have suggested that marijuana use has minimal
or no effect on the likelihood of crash involvement,
while others have estimated a small increase in the risk of
crash involvement."

"The Li study estimated the increased risk of crash involvement
for drivers using marijuana at 1.83 times that of drug-free
drivers, while the Romano study found no increased risk
of crash involvement for those drivers testing positive
for THC (the main psychoactive substance in marijuana)."

NT News

TERRITORY stoners and medicinal marijuana smokers are becoming increasingly paranoid they will be caught out by tougher drug-driving laws.

But Police Minister Peter Chandler said there would be no leniency for medicinal marijuana smokers when the new laws come into effect on February 1.

Drivers face lengthy driving bans and thousands of dollars in fines for returning a positive test. The NT News has spoken to cannabis smokers worried they will be penalised despite not being under the influence of the drug.

One casual drug user said there was a subculture of Territory cannabis smokers who used cannabis responsibly.

He said there was a difference between casually smoking cannabis and driving after smoking meth.

“We are organised people. We have got a family and kids. When the kids go to bed at night we’ll indulge in a chuff,” he said.

“There’s quite a few people that indulge in marijuana frequently and no other drug. They enjoy that and they are no harm to the community.

“We’re made to be instant criminals straight away.”

A medicinal cannabis user said he used the drug to ease the pain of his illness.

But Mr Chandler made no apology for the tough stance.

“There will be a zero tolerance approach to drivers who drive under the influence of drugs. Any trace of prohibited drugs in your system will result in a penalty – cannabis, ice or ecstasy, no drug is excluded,” he said.

“All drugs are illegal and if you’re caught risking your own life and the lives of others you will be prosecuted. There is a simple solution. Don’t take drugs.

“Cannabis – even medicinal cannabis – isn’t legal in the Northern Territory. If you’re driving under the influence of cannabis then you’re both a fool and committing a crime.”

Drug drivers face two categories of penalties if they return a positive test and a lab analysis confirms the presence of illicit substances.

A driver caught with traces of drugs in their system is issued with a $400 on-the-spot fine.

For a second offence, drivers face a minimum three-month disqualification, a $1200 fine or six months in prison.

However, drivers face a six-month driving ban, a $1500 fine or 12 months in prison if caught driving under the influence of illicit substances.

The penalty doubles for a second offence.

reference; NT News

US Department of Transport